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SYSTEM OF LOGIC, 



COMPRISING 



A DISCUSSION OF THE VARIOUS MEANS OF ACQUIRING AND 
RETAINING KNOWLEDGE, AND AVOIDING ERROR. 



by p. McGregor, a.m. 



r 



NEW YORK: 

HARPER & BROTHERS, PUBLISHERS, 

FKANKLIN SQUARE. 

186 2. 






Entered, according to Act of Congress, in the year one thousand 
eight hundred and sixty-two, hy 

HARPER & BROTHERS, 

In the Clerk's Office of the District Court of the Southern District 
of New York. 



PREFACE. 



The following treatise is the result of an attempt 
to comprise within moderate limits everything of 
general interest which properly belongs to, Logic, free 
from prolixity, obscurity or misrepresentation. Much 
that occurs in other works on the same subject, has 
been rejected us useless, irrelevant or erroneous, while 
I have endeavored to supply numerous deficiencies, 
and to exhibit a woar and accurate view of the prin- 
ciples and processes of logical thought, divested of 
scholastic figments, which only perplex and mislead 
the student. 



CONTENTS. 



INTKODUCTION. . 

TAGT! 

§ 1. Nature, Foundations, and Limits of Logic 13 

§ 2. Objects, Uses, and Study of Logic. 14 

§3. Advantages of Knowledge, and Evils of Ignorance 15 



PART I. 

OF THE ULTIMATE SOURCES AND ELEMENTS OF KNOWLEDGE, AND 
THE PRIMARY PROCESSES BY WHICH IT IS ACQUIRED AND RE- 
TAINED. 

CHAPTEE I. 

A GENERAL VIEW OP THE LIMITS, DIVISIONS, AND IMMEDIATE 
SOURCES OF KNOWLEDGE. 

§ 1. Necessary Limits and principal Divisions of Knowledge 2D 

§ 2. Of the various Faculties by which Knowledge is acquired 

and retained 32 

§ 3. Of Propositions 37 

§ 4. Of Probability 40 

§ 5. General Criterion of Truth, and immediate Source of Error 45 

CHAPTER II. 

OP REASONING. 

§ 1. Nature, General Principle, and Expression of Reasoning ... 49 

§ 2. Special Principles of Reasoning 52 

§ 3. Processes and Criterions of Reasoning 65 

CHAPTER III. 

OF THE PRIMARY MEANS OP ACQUIRING CONTINGENT KNOWLEDGE. 

§ 1. Reality of Apprehensions, and Means of avoiding the pri- 
mary Errors which they directly occasion 71 

§ 2. Primary mental Processes by which contingent Knowledge 

may be acquired 75 

§ 3. Primary external Processes by which contingent Knowledge 

may be acquired 8G 



vi Contents. 

CHAPTER IV. 

OF THE PRIMARY MEANS OF RETAINING KNOWLEDGE. 

PAGK 

§ 1. Reliability of Memory, and Means of avoiding the primary 

Errors which it tends to produce 93 

§ 2. Primary Processes by which Knowledge is retained 96 

CHAPTER V. 

OF GENERALIZATION. 

§ 1. Nature of Generalization 1 98 

§ 2. Principal Processes of Generalization 99 

§ 3. Extension and Uses of Generalization 107 

CHAPTER VI. 

OF HYPOTHESES. 

§ 1. Nature and Uses of Hypotheses 109 

§ 2. Methods of testing Hypotheses 113 



PART II. 

OF THE PRINCIPLES AND METHODS OF INVESTIGATION. 
CHAPTER VII. 

OF INVESTIGATION IN GENERAL. 

§ 1. Of Dispositions affecting Investigation 119 

§ 2. Of Habits affecting Investigation 121 

§ 3. Of Things which require no Proof 127 

§ 4. Of Things which may generally be admitted as proved 129 

§ 5. General Modes of determining the Validity of Proofs 13-4 

CHAPTER VIII. 

OF STUDY. 

§ 1. Nature and Uses of Study 139 

§ 2. Subjects, Modes, and General Rules of Study 140 

§ 3. Selection and Study of Books 148 

.CHAPTER IX. 

OF ORIGINAL INVESTIGATION. 

§ 1. General Character, Uses, Prerequisites, and Methods of 

Original Investigation ? 1^1 

§ 2. Of Direct Discovery J5 5 

§3. Of Indirect Discovery 15G 

§ 4. Of Invention 162 



Contents. vii 

CHAPTER X. 

OP CAUSES AND EFFECTS. 

PAGE 

§ 1. Sources and Applications of the Knowledge of Causes and 

Effects '. 165 

§ 2. Various Kinds of Causes 169 

§ 3. Methods of determining Causes andEffects 171 

CHAPTER XI. 

OF LANGUAGE. 

§ 1. Origin and Progress of Language 182 

§ 2. Uses of Language 189 

§ 3. Imperfections and Abuses of Language 194 

§4. Interpretation of Language 200 

CHAPTER XII. 

OF EVIDENCE. 

§ 1. General Principles of Evidence 209 

§ 2. Criterions of Testimony 212 

§ 3. Various Kinds of Testimony, and Peculiarities of each 226 

§ 4. Means of ascertaining the Origin and Character of Written 

Testimony 228 

CHAPTER XIII. 

OF CLASSIFICATION. 

§ 1. Nature and Uses of Classification 238 

§ 2. Principles and Methods of Classification 240 

CHAPTER XIV. 

Tabular View of the Means of acquiring Knowledge 246 



PART III. 

OF FALLACIES. 
CHAPTER XV. 

NATURE AND CLASSIFICATION OF FALLACIES. 

§ 1. Nature of Fallacies 249 

§ 2. Classification of Fallacies 250 

CHAPTER XVI. 

SOURCES OF FALLACIES, AND MEANS OF GUARDING AGAINST THEM. 

§ 1. Sources of Fallacies 252 

§ 2. Of Prejudices 254 

§ 3. Means of guarding against Fallacies 260 



viii Contents. 



CHAPTER XVII. 

OP PARALOGISMS, OR FALLACIES OP PRIMARY ASSUMPTION. 

PAGE 

§ 1. Paralogisms of Intuition ., 266 

§ 2. " " assuming what is attempted to be proved.... 267 

§3. " "Comprehension 269 

§4. " "Signs 271 

§5. " "Memory 274 

§ 6. Intrinsic Paralogisms of Testimony 275 

§ 7. Extrinsic " " 280 

§ 8. Paralogisms of Misinterpretation of Language 283 

CHAPTER XVIII. 

OP SOPHISMS, OR FALLACIES OP INTERMEDIATE REASONING. 

§ 1. Sophisms of Confusion 287 

§2. " "Generalization 289 

§3. " "Causation 292 

§4. " "Probability 298 

CHAPTER XIX. 

OF AEERRANCIES, OR FALLACIES OF IRRELEVANCY. 

§ 1. Aberrancies of Confusion 306 

§2. " " Appeals to Authority 316 

§3. " " Appeals to Desires..'. 320 

CHAPTER XX. 
Table of Fallacies 325 



PART IV. 

A SPECIAL SURVEY OP THE PRINCIPAL BRANCHES OP KNOWLEDGE. 
CHAPTER XXI. 

CLASSIFICATION OF KNOWLEDGE, ACCORDING TO ITS SUBJECTS. 

§ 1. Scientific Knowledge 331 

§2. Mixed " 339 

§3. Particular " 340 

§ 4. Tabular View of Knowledge 341 

CHAPTER XXII. 

OF MATHEMATICS. 

§ 1. Peculiarities of Mathematics 344 

§2. Uses " " 346 

§3. Study " " 347 



Contents. ix 

CHAPTER XXIII. 

OF THE PHYSICAL SCIENCES. 

PAGE 

§ 1. Of the Physical Sciences in general 351 

§2. " Mechanical Sciences 352 

§3. " Ethereal " 358 

§ 4. " Organical " .... 362 

§5. " Geographical " 367 

CHAPTER XXIV. 

OF THE MENTAL SCIENCES. 

§ 1. Of the Mental Sciences in general 374 

§ 2. Of Logic and Psychology 376 

§ 3. Of Theology 377 

§ 4. Of Morality, or Ethical Science 381 

§ 5. Of Jurisprudence 383 

CHAPTER XXV. 

OF MIXED KNOWLEDGE. 

§ 1. OfPhilology 385 

§ 2. Of Ethnography 391 

§ 3. OfTechnology 392 

CHAPTER XXVI. 

OP PARTICULAR KNOWLEDGE. 

§ 1. Of History 396 

§ 2. Of Chronology 402 

§ 3. Of Biography 403 

CHAPTER XXVII. 

OP THE KNOWLEDGE OP FUTURITY. 

§ 1. Of the Knowledge of Futurity in general 405 

§ 2. Sources of our Knowledge of Futurity 406 



PART V. 

OF THE RETENTION OF KNOWLEDGE. 
CHAPTER XXVHI. 

OP THE RETENTION OP KNOWLEDGE BY SIMPLE REMEMERANCE. 

§ 1. General Laws and Rules of Remembrance 413 

§ 2. Of the Relations of Thoughts 419 

A 2 



x Contexts. 



CHAPTER XXIX. 

OF THE RETENTION OF KNOWLEDGE BY MEANS OF EXTERNAL 

SIGNS. 

PAGE 

§ 1. Of External Signs in general 425 

§ 2. Of the Retention of Knowledge by "Writing 427 

CHAPTER XXX. 

OF THE MEANS OF POSSESSING A READY COMMAND OF OUR 
KNOWLEDGE. 

§ 1. Requisites to possessing a ready Command of our Knowl- 
edge 429 

§ 2. Means of acquiring and employing the preceding Requi- 
sites 431 

CHAPTER XXXI. 

Tabular View of the Means of retaining Knowledge 434 

Notes 435 

Index 449 



INTRODUCTION. 



SYSTEM OF LOGIC. 



INTRODUCTION. 

§ 1. Nature, Foundations, and Limits of Logic. — Subjects and 
Definition of Logic. — On what founded. — Advantages of uniting 
its three principal subjects in one Science. — Why the communica- 
tion of Knowledge i& excluded. 

Logic is the science which exhibits the foundations 
and primary elements of knowledge, the proper means 
of investigating truth, the nature and sources of errone- 
ous opinions, the modes in which we must proceed in 
order to secure the former and avoid the latter, and the 
best methods of retaining knowledge after it has been 
acquired. It may, therefore, be defined the science of 
the acquisition and retention of knowledge, and the 
means of avoiding error. It is founded on the follow- 
ing principles, the truth of which becomes evident from 
a slight consideration (1).* 

1. We have only one set of intellectual f amities, the 
laws of lohose proper exercise are identical, throughout 
the numerous fields of human inquiry. Thus we have 
not one faculty of vision for Botany and another for 
Chemistry, nor one faculty of reasoning for Morality and 
another for Geology ; and, in order to sound reasoning, 
the premises must necessarily imply the conclusion pro- 
fessedly inferred from them, whatever be the subject of 
consideration. 

2. Those facidties operate uniformly, and are liable to 
mislead us only in certain ways. Thus the senses al- 
ways operate by impressions on the nerves, through 
which corresponding impressions are produced in the 
seat of consciousness ; and they are liable to mislead us 
only by presenting something which appears like a dif- 
ferent thing. So Reason constantly operates by show- 
ing that one thing necessarily implies another; and it 

* The figures at the ends of paragraphs refer to the notes, which 
precede the Index. 



14 Introduction. 

can occasion error only by leading us to believe that this 
is the case, when in reality it is not. 

The acquisition and retention of knowledge, and the 
means of avoiding error, form subjects sufficiently con- 
cise and connected to be discussed as one science ; and 
we throw unnecessary obstacles and dangers in the way 
of the inquirer, if we separate them, and, after furnishing 
him with a part, either leave him to think he has mas- 
tered the whole, when in reality he has not, or tacitly re- 
fer him to some unknown quarters, for a knowledge of 
several of its most important parts, of which he is still 
ignorant. 

The propriety- of* including the retention of ii.no wi^uge 
will be readily perceived, by observing that it is not suf- 
ficiently extensive to form a separate science, while it is 
essential to render knowledge available. In order to be 
of any value, truth must not only be discovered, but se- 
cured in such a manner that we can bring it before the 
attention at pleasure. It is further to be observed that 
many truths can be discovered only by retaining in the 
memory many others previously acquired. 

The subject of the communication of knowledge should 
be excluded from Logic, on account of its great extent 
and its distinct nature. 

§ 2. Objects, Uses, and Study op Logic. — General and special 
objects of Logic. — Its Utility. — Study of Logic. — Who may study 
it successfully. 

Logic is designed to aid us in every inquiry, and not 
to dispense with any other science. Its general object 
is, to show the capacity of our intellectual faculties, and 
the modes in which they must be employed, in order to 
acquire and retain knowledge, and avoid error. Its prin- 
cipal special objects are — (l) to assist us in determining 
the truth of any given proposition — (2) to guard us 
against the errors which we are liable to adopt, in the 
various departments of investigation — (3) to furnish all 
the other aids which general discussions and directions 
can supply, in the pursuit of knowledge — (4) to point 
out the best means of retaining our intellectual acquisi- 
tions, so that we may use them at pleasure — and (5) to 
give us the proper degree of confidence in our intellects, 
so that we may avoid both dogmatism and skepticism. 

A man who has ascertained the laws of proper inves- 



Sec. 2.] Objects, Uses, &c, op Logic. 15 

tigation and the sources of error, will evidently deviate 
from the paths of truth much less frequently than one- 
who differs from him only in having paid no attention 
to those subjects, and who may consequently be led un- 
awares, by some common prejudice or illusion, into a 
wrong path, from which he would have been restrained 
by a knowledge of Logic. To investigate some points 
rightly, and to know the nature and conditions of proper 
investigation, are very different thingsy v the latter of 
which is never acquired without study, and can rarely 
be acquired at all without the aid of Logic, while it is 
of great value in all the most important fields of human 
inquiry. 

The utility of Logic appears from the fact that we can 
never adopt an erroneous opinion without first violating 
one or more of its principles, just as a person cannot 
commit a solecism in language without ''-first violating 
some rule of Grammar. 

In order that Logic should answer its objects, its prin- 
ciples and rules must be well understood and remember- 
ed : for otherwise they will be overlooked, and conse- 
quently violated, at the very time when their aid is most 
requisite. Its various parts should, therefore, be studied 
with such care that there will be no danger of misunder- 
standing them ; and the more important parts should be 
repeatedly reviewed, until they are permanently impress- 
ed on the memory. The student should particularly be- 
ware of adopting false views of those rules and princi- 
ples : for, as they are applicable to all investigations, he 
will thus lay the foundations of error on every other sub- 
ject. 

Logic may be mastered without any previous prepara- 
tion or extraordinary abilities : and, therefore, it may be 
studied successfully by any person who will bestow on it 
a little care and labor, while it requires much less of ei- 
ther than some other subjects of comparatively little im- 
portance. 

§ 3. Advantages op Knowledge, and Evils of Ignorance. — 
Benefit of understanding the value of Knowledge. — Its various Ad- 
vantages: (1) Its effects on the main pursuits of our lives. — Evils 
arising from mistaken views. — How Knowledge would prevent them. 
— (2) Its effects on the Emotions. — (3) Pleasures derived from it. — 
(4) Its influence on evil Habits — (5) on physical Welfare and Safety 
— (6) on Morality — (7) on Impositions — (8) on Superstition — and 
(9) on mental Discipline. —Evils of Ignorance. — Threefold Benefit 



16 fceEBODrcriox. 

of the proper acquisition of Knowledge. — Bearing of this section 
on Logic. 

The pursuit of knowledge is often much less pleasant, 
for the time being, than that of sensual pleasure, gain, 
fame, or amusement ; and, even when we have engaged 
in it, we are liable to be led astray by doing that which 
is easiest and most pleasant at the moment. Hence it is 
necessary that we should clearly see the benefits which 
result from advancing actively and circumspectly in the 
right course, in order that the subject may receive prop- 
er attention. The following are the principal advantages 
of knowledge. 

1. Knowledge is indispensable to prevent us from be- 
ing fatally mistaken, regarding the main pursuits of 
our lives. For, in order to this, we must choose proper 
ends, and right and judicious means of accomplishing 
them, while the ignorant cannot know what ends are 
proper, or what are the best means of securing them. 
The ends at which he aims, are what particularly distin- 
guishes a wise from a crafty man. The latter often ex- 
hibits much ingenuity and activity in effecting his ends : 
but, as he never sufficiently considers the end, he only 
secures and accelerates his own ruin ; and, the more pow- 
er he possesses, the worse for himself and those connect- 
ed with him. 

Striking instances of the evils which result from igno- 
rance on this subject, are furnished by the innumerable 
votaries of sensuality, avarice, vanity, and ambition, who 
have formed a great majority of mankind, up to this day. 
They have all thought themselves on the highway of 
happiness, while they were treading the paths of lasting 
misery. They have erred, not only in expecting too 
much from their favorite objects, but in overlooking 
others, of much more consequence. Even where the 
general object of their pursuits was proper, they have 
erred egregiously regarding its comparative importance. 
The accumulation of money, for example, may be proper- 
ly sought by right means and to a reasonable extent ; 
but the case is greatly altered when it is made the para- 
mount object of life, and pursued through right and 
wrong, by men who have paid no attention to much more 
important matters, of which they are profoundly igno- 
rant. 

Xo person knowingly blasts his own permanent wel- 



Sec. 3.] Advantages oe Knowledge. 17 

fare ; and hence this is always done ignorantly, and if 
the individual knew more, he would act differently. Some 
frequently confess that they are acting foolishly : hut all 
they mean, is, that such conduct is deemed foolish hy 
others, or that it may possibly lead to some disagreeable 
consequences, the real nature and extent of which, how- 
ever, they do not consider, and consequently do not know, 
while they think that these will be more than counter- 
balanced by the benefits which they expect from the 
course pursued. Every one necessarily does what he 
deems best at the time, upon the whole ; and hence those 
follies are inevitably accompanied by gross ignorance on 
many important subjects, although this is generally cul- 
pable, and, therefore aggravates, instead of palliating, the 
guilt of their conduct. 

In order to answer the purpose, knowledge must re- 
late to the particular subject in hand : a knowledge of 
Mathematics will not supply the place of an acquaintance 
with Physics, and much less with Psychology or Moral- 
ity, any more than a superabundance of water will sup- 
ply the place of solid food. In order to permanent hap- 
piness, which must be the main object of every enlight- 
ened mind, we must know where it lies, and the course 
which we must adopt in order to secure it. But when 
we have learned the real nature and sure tendency of dif- 
ferent pursuits and practices, we can choose proper ends ; 
and a knowledge of our duties, and the ways in which 
these ends can be rightly effected, will prevent us from 
erring fatally or seriously in the pursuit. 

2. Knowledge is requisite in order to the due exercise 
and regidation of the emotions, on which happiness 
mainly depends. The emotions are not directly under 
the control of the Will, but are excited by the contem- 
plation of then' respective objects ; and, consequently, 
these must be perceived by the mind before the emotion 
can be excited, while the mind can never perceive any- 
thing of which it is totally ignorant. Thus we cannot 
sympathize with the joys or sorrows of others unless we 
know what they are ; and we cannot feel affection and 
Teverence for the Eternal, unless we learn those attributes 
of his character which alone excite these emotions to- 
wards him. 

That happiness depends mainly on the due exercise of 
benevolent and sympathetic emotions, and the suppres- 



18 LyTEODrCTIOX. 

sion or eradication of those of a contrary kind, is proved 
by observation, and by the known force of such emotions. 
Let a man surrounded with all physical comforts and en- 
joyments only have some strong malevolent emotion ex- 
cited, and he immediately feels unhappy. On the other 
hand, let one destitute of many of those advantages have 
his mind filled with strong pleasant emotions — regardino- 
the past, the present or the future — and he is happy while 
under their influence. Xow there are always objects 
within the reach of our mental vision which excite such 
emotions : but we must diligently search for them and 
keep them in view, in order to benefit by them ; and this 
requires a knowledge of the nature and importance of 
those emotions, which are undervalued by the ignorant, 
because they do not striE :- the attention like objects of 
sense. 

3. Knowledge furnishes various direct pleasures which 
canfiot be ed by the ignorant. The absorbing in- 

jrest which the Mathematician and the Philologist fre- 
quently feel in their studies, is a striking instance 
direct pleasure derivable from knowledge, even in its 
most abstract form: and although these are studies in 
which the majority of mankind cannot be expected to 
feel a deep interest, yet the case is otherwise with vari- 
ous departments of knowledge. If we except the few 
who are insane, or only a little above idiocy, all mankind 
delight in observing the beauties and wonders of nature. 
Many, also, feel much interested in witnessing great and 
stirring historical scenes : and although these may be 
placed beyond the reach of observation, yet the pai 
Hist :ry disclose them, in countless numbers. To persons 
who prefer tracing the lives of distinguished or remark- 
able individuals, Biography offers an extensive field of 
similar enjoyment. 

The sources of these pleasures are as varied as the 
subjects of thought. For, besides the mathematical and 
hysical sciences. Ethnography. History and Biography, 
there is the wide field of the mental sciences, which will 
ever possess the strongest attractions for all who desire 
to penetrate to the causes of observed phenomena, and 
trace the ultimate laws by which they are regulated. 

There are not only different fields of enjoyment, but 
also various subdivisions of the same field, so that every 
individual's precise taste may be gratified. He who dis- 



Sec. 3.] Advantages of Knoavledge. 19 

relishes the stormy scenes of politics or war, may trace 
the progress of religion, science and literature, or study 
the history of manners and social life ; he who delights 
in contemplating external nature, as it is presented to 
our immediate view, can study Geography, while those 
who prefer to analyse its materials, may study Chemistry 
and Geology: one who desires to contemplate vast ob- 
jects, may have recourse to Astronomy; and he who 
would inspect the minute works of the Creator, can study 
Physiology and Entomology, while those who wish to 
examine the inventions of man, are-furnished with an ex- 
tensive field, in the various processes and results of Art. 

Nor do those pleasures, by any means, end with the 
first acquisition : for they may be renewed whenever we 
choose to recollect the objects which first excited them; 
and although much may have been forgotten, yet the 
most striking and impressive parts will generally be re- 
membered, on account of the strong attention and feel- 
ing which they originally excited. 

4. Knowledge is necessary to prevent mankind from 
addicting themselves to evil practices which mar their 
happiness. The desire of enjoyment exists constantly in 
every mind : and hence those who are unacquainted with 
the pleasures which accompany knowledge, and are nev- 
er obtained by the ignorant, devote themselves to the 
only enjoyments of which they know. From this source 
have sprung the various forms of sensuality, with the 
fearful evils which they have inflicted on the human race, 
and many pastimes which exert a most disastrous influ- 
ence on their devotees. Yet such enjoyments w T ill ever 
be eagerly sought by those who have found nothing bet- 
ter ; and this can be done only by acquainting ourselves 
with the mighty and wonderful works of God, the treas- 
ures of Science and Art, the records of History and Bi- 
ography, and the numerous objects which exercise our 
sympathies, and require our active efforts, throughout the 
world. 

Those various subjects are much more than sufficient 
to occupy all the time that can be spared from important 
duties ; and they furnish a field of harmless and exalted 
enjoyment which the longest life and most diligent study 
can never exhaust. When we learn to enjoy such pleas- 
ures, and at the same time know the great evils that re- 
sult from those practices, it will not be a difficult matter 



20 Introduction. 

to discontinue them forever. For such knowledge dis- 
closes to us those objects which excite our strongest and 
purest emotions, as well as the worthlessness of those 
practices as means of happiness, and the numerous priva- 
tions and sufferings which they entail on their votaries. 

5. JZnowledge is requisite to our physical welfare and 
safety. The value of the useful arts, for these purposes, 
is obvious ; and although the dependence of many of 
them on sciences apparently of no practical application 
is not so easily seen, it is not the less real. A knowledge 
of the properties of abstract quantity seems, at first sight, 
to be utterly removed from the business of life ; yet it 
forms the foundations of many important arts, and of the 
science of Astronomy, whose aid is requisite to enable 
the navigator to cross the ocean in safety, and convey 
the superabundant food of one hemisphere to the famish- 
ing millions of another. So the discoveries of the Chem- 
ist, the Botanist, and the Physiologist, improve the art of 
Agriculture, and promote the preservation and restora- 
tion of health. 

"Without the aids furnished by superior intelligence, 
man would be in a worse condition than the lower ani- 
mals : for in childhood he is helpless, and he comes to 
maturity very slowly ; he is destitute of natural clothing 
or means of defence ; he is much inferior to many of the 
brutes in bodily strength ; and the spontaneous produc- 
tions of the earth do not suffice for his sustenance. Hence 
not only his welfare, but his very existence is wholly de- 
pendent on his superior knowledge. 

We are incessantly surrounded by agencies, and tempt- 
ed to yield to certain allurements, which tend to injure 
health and produce premature death ; and, in order to 
escape the bad effects of exposure to their influence, we 
require a knowledge of their nature, and of the proper 
means of guarding against them, which is often unattain- 
able without extensive and careful investigation. 

It is only by the aid of knowledge that men will in- 
dustriously follow proper methods for supplying their 
physical wants, or secure the fruits of their labor, and 
make a right use of them after they have been acquired. 
But a knowledge of God, of man, and of external nature, 
produces industry, justice, abundance of everything req- 
uisite to supply our physical wants, temperance in the 
use of them, a proper degree of care against external 
dangers, and a general observance of the laws of health. 



Sec. 3.] Advantages of Knowledge. 21 

The physical welfare of a community also requires 
many conveniences which can be furnished only where a 
dense population admits of a great division of labor, 
while such a population cannot exist happily without an 
extensive and accurate knowledge of the art of cultiva- 
ting the soil, and of the proper modes of regulating the 
distribution of its productions. For otherwise the lar- 
ger portion of the community will inevitably suffer from 
want, and drag on a wretched existence, surrounded by 
the strongest temptations to vice. 

6. Knowledge is necessary to secure common morality, 
and render ordinary business safe and agreeable. We 
are beset by various inducements to act immorally to- 
wards others, so strong that we shall frequently yield to 
their influence, unless we are fortified against it by a 
knowledge of the motives to virtue, and the sure conse- 
quences of vice. Hence serious offences of this kind will 
always abound among a people ignorant on the subject 
of their duties, and an ignorant community is addicted 
to several vices, against which he who deals with its 
members must incessantly guard, in order to avoid seri- 
ous pecuniary loss, and other great evils incident to such 
intercourse. 

The prevalent vices of nations and individuals widely 
vary ; and as every one is apt to look at the bright side 
of his own and the dark side of his neighbours' character, 
he readily concludes that he is, upon the whole, tolerably 
virtuous, while an impartial observer might find that both 
are equally immoral, their respective failings differing only 
in kind, and not in degree. 

The general connection between ignorance and crime 
is shown by the fact that, in every intelligent communi- 
ty, the majority of criminals belongs to the small fraction 
of society which is illiterate, and that the slaves of vice 
are uniformly found to be grossly ignorant regarding the 
nature and sanctions of morality. They frequently know 
something on these subjects ; but their views of them 
are radically erroneous. Knowledge removes such evils, 
by imparting proper affections towards others and steady 
moral principles. 

7. Knowledge guards tcs against the numberless impo- 
sitions that are practised on the ignorant, by the design- 
ing and unprincipled. Impositions of this kind often 
enable men to obtain others' property without giving a 



22 Ixteoduction. 

fair equivalent in return, while they escape the penalties 
attached to robbery or theft ; and hence the extreme 
prevalence of such frauds, which have produced much 
evil. Ignorance and its ordinary concomitant, credulity, 
may be said to be the capital on which the various class- 
es of deceivers and impostors have traded in all ages : 
and they disappear only where men have become too en- 
lightened to be deceived ; for the same bad training that 
makes one man a credulous dupe, will make a person of 
a different disposition a cheat. 

Frauds and impositions have been extremely common, 
on account of the wide field presented by ignorant cre- 
dulity, and because there are as many temptations t ■:■ 
deceptions as there are evil passions or depraved appe- 
tites. Yet a knowledge of the devices and falsehood :' 
the unprincipled, the criterions of truths, and th : 
nature, would banish all these evils from society A 
very ordinary knowledge of Physiology and Pathc 
for example, would enable us to detect the impos;.: us 
of a quack, who professed to cure all diseases with 
gle nostrum: a knowledge of the character of God and 
the nature and condition of man, would banish religions 
deceptions : the young and unwary would escape the 
snare, if they knew the character and objects of the in- 
snarer : and men would very rarely believe any false as- 
sertions, if they were well acquainted with the requisites 
of credible testimony and the sources of error. 

3. Knowledge is requisite to free the mind from su- 
perstition. History abounds with instances of the dis- 
mal effects which have flowed frorn this source. Under 
its influence, the most civilized and enlightened nations 
of antiquity became addicted to the vilest and most cruel 
practices, even to murdering their own offspring and im- 
molating themselves, in order to appease the snj' 
wrath or procure the favor of deities that existed only 
in their own benighted imaginations. And even where 
those more revolting superstitions passed away, the pu- 
erilities and disgusting practices of succeeding times de- 
based the mind, and shut out the fight of truth. Super- 
stition not only produces particular evils, but also substi- 
tutes its own worthless forms and pernicious doctrines 
in the place of truth, and generally surrounds the minds 
of its victims with a web of prejudices and errors," 
renders them satisfied with fatal ignorance. 



Sec. 3.] Advantages of Knowledge. 23 

Wherever true religion is absent, superstition inevita- 
bly appears: for the phenomena of nature lead, us irre- 
sistibly to a superior power, of which our conceptions 
must be either accurate or the reverse ; and the belief in 
a future state is too deeply rooted in our nature to be 
eradicated by any sophistry, however subtle. Hence 
some form of superstitious belief and practice exists 
wherever jaeople's views of the superior power and a fu- 
ture state are radically erroneous. But a knowledge of 
the character and government of the only true God, of 
the relation in which Ave stand to him, and of the laws 
of nature, banishes superstitious opinions and practices, 
as the effects disappear with their cause. 

9. The acquisition of knowledge is requisite to dis- 
cipline the intellect, and fit it for a proper performance 
of duty. It is a matter of daily observation that the 
characters of persons and the amount of good which they 
effect, depend much more on their training than on the 
native force of their understandings. Many men of or- 
dinary abilities become, by proper mental discipline and 
instruction, happy and useful members of society, while 
others, of great native talents, have often, for want of 
these advantages, spent miserable lives, and were justlv 
regarded as public pests. 

The intellectual, like the corporal, faculties require sni - 
able exercise, in order to the proper performance of those 
functions for which they were conferred, while such ex- 
ercise is found only in a proper course of study and ob- 
servation, for the attainment of knowledge. As a man 
cannot be made a good sailor by following the plough, 
so a person cannot be fitted for properly discharging his 
various duties, unless his intellect has been exercised on 
those very subjects with which he is to be conversant in 
after life. In order to discharge our duties towards God 
or man, we must possess a correct knowledge of the di- 
vine character ; and this is unattainable unless our minds 
are properly trained in investigating his works and 
words. 

Ignorance inevitably leads to innumerable pernicious 
errors, both of opinion and practice. We must think and 
ac£; and unless we are guided by knowledge, we shall 
both think and act in such a manner as not only to miss 
the great object of all our pursuits, but also to inflict 
many serious and permanent evils upon others. On many 



24 Introduction. 

subjects, ignorance is evidently so dangerous and disre- 
putable that men are not satisfied without possessing 
something which will pass for knowledge, while they 
may be, in reality, so ignorant that they readily adoj)t 
for truth errors recommended by their own prejudices 
or the authority of persons in whom they confide, with- 
out ever mistrusting that there is anything wrong. 

Besides religion; we meet with opinions on many other 
subjects, firmly believed by the unenlightened portion 
of mankind, which men acquainted with those subjects 
know to be totally false. Such are, the opinion that some 
persons are lucky and others unlucky, independently of 
character, conduct and circumstances ; that, by means of 
certain simple manipulations, a person can be made to see 
better without than with the use of his eyes ; that men 
can perform miracles by means of satanic agency ; that 
certain diseases can be cured by rubbing the affected 
part to a corpse — and so forth. 

Thus ignorance not only excludes knowledge, but sub- 
stitutes in its place a spurious belief, much worse than 
none. 

Some have maintained that ignorance is favorable to 
happiness, and knowledge dangerous and pernicious. 
But happy ignorance exists only in the realms of pure 
imagination. We have the highest authority for assert- 
ing that, in ancient times, the people perished for want 
of knowledge ;* and the need of it is equally great in ev- 
ery age. We are also told that ignorance is an evil, and 
knowledge a great good,f statements which are confirm- 
ed by all the annals of our race. Certain kinds of knowl- 
edge are liable to be abused : but this cannot occur with 
a man who knows his duties, and is at the same time in- 
fluenced by those emotions and moral principles which 
uniformly accompany an accurate and extensive acquaint- 
ance with the most important subjects of human investi- 
gation : and hence the evils attributed to knowledge are, 
in reality, the effects of ignorance. 

From the preceding survey, we see that the proper ac- 
quisition of knowledge furnishes three distinct advant- 
ages : 1. It supplies the information requisite to right 
conduct, and to avoid pernicious courses. 2. It trains 

* Prophecies of Hosea, chapter iv., verse 6. 

t Proverbs of Solomon, chapter xviii., verse 15 ; chapter xix., verse 
27 ; and Ecclesiastes, chapter vii., verse 12. 



Sec. 3.] Advantages op Knowledge. 25 

the faculties, and renders them able to perform their func- 
tions properly. 3. It affords various direct enjoyments, 
which can be repeated indefinitely. 

The degree of knowledge requisite for the purposes 
mentioned, is not attainable except by means of investi- 
gations conducted in accordance with the principles of 
Logic ; and these require to be studied, in order to be 
known. This is proved by the grave errors and mis- 
takes committed by many investigators, and the igno- 
rance or erroneous opinions of a great majority of man- 
kind, on all the most important subjects, from the earli- 
est times to this day. 

B 



PART I. 



OF THE ULTIMATE SOURCES AND ELEMENTS OF 

KNOWLEDGE, AND THE PRIMARY PROCESSES 

BY WHICH IT IS ACQUIRED AND 

RETAINED. 






CHAPTER I. 

A GENERAL VIEW OP THE LIMITS, DIVISIONS, AND IMME- 
DIATE SOUKCES OP KNOWLEDGE. 

§ 1. Necessary Limits and Principal Divisions of Knowledge. 
— (1) Knowledge limited to Intuitions, Comprehensions, and Infer- 
ences. — Peculiarities of these several classes. — Boundaries of the 
Knowable and of the Known. — Distinction between Knowledge and 
Belief. — (2) Knowledge either Mediate or Immediate. — Definition 
of Cognition, Consciousness, and Discernment. — Truths known by 
the latter. — (3) Knowledge consists of Necessary, Contingent, and 
Hypothetical Cognitions. — Branches belonging to each. — Common 
properties of all. 

1. Everything which we can know, must belong to 
5 one or other of the three following classes of truths. 

(1) Those which are self-evident, or which we know 
must be such, and cannot possibly be otherwise, inde- 

- . pendently of anything made known to us by our senses. 
Such are, the existence and essential nature of time and 
space — that contradictories cannot co-exist, and that a 
thing is equivalent to itself. These we term intuitions, 
and the faculty or power by- which we know them In- 

v tuition. 

(2) Truths not necessarily such, but made known to 
-^ us directly by Comprehension, the faculty by which we 

directly know truths which are not self-evident. Thus, 
when we behold the sky, we certainly see a blue expanse ; 
when we smell a rose, we feel a particular odor ; Avheu 
Ave have succeeded in effecting a difficult object which 
we deem important, we feel a pleasant emotion ; and 
when we think of a tree which Ave have often seen, We 
have an idea of its appearance. Truths of this class Ave 
term comprehensions. 

(3) Inferential truths, or those which are necessarily 
implied in intuitions, comprehensions, or suppositions, 
and which we term inferences. By necessary implica- 
tion is meant, such a connection that the inferences must 
be true, and cannot possibly be false, if the things from 
which they are inferred are true. 

These three classes of truths include everything that 






30 Linns a^td Sources of Knowledge. [Chap. I. 

can possibly be known : for it is evident that we cannot 
possibly know a thing if it is not knowable by any of the 
faculties by which we obtain direct knowledge, nor sus- 
ceptible of being found to be implied in anything which 
we can either know or suppose. Hence — (1) any inves- 
tigation which lies beyond these bruits is fruitless, such 
as an inquiry into the origin of life, or the atomical struc- 
ture of matter — (2) everything within these limits is 
knowable — and (3) no statement is entitled to be classed 
with known truths, till it has been clearly ascertained to 
be an intuition, a comprehension, or an inference. 

It is also evident that everything which we actually 
know, must be known directly or indirectly, and that 
whatever is known directly must be so because it is 
known to be either self-evident or presented by some 
faculty that we possess of directly knowing truths which 
are not of the former class. It is equally evident that a 
truth can be known indirectly only in consequence of its 
being found to be necessarily connected with something 
that is known directly. Hence the intuitions, compre- 
hensions and inferences which a person knows to be 
such, form all his actual knowledge. Intuitions and in- 
ferences not known to be such, things once comprehend- 
ed but afterwards totally forgotten, and things never 
comprehended, evidently form no part of our actual 
knowledge. 

JTnoicIedge can be only of truths: for although we 
may believe error we cannot know it, since this implies 
that it is either a truth known directly to be such, or 
that it is sustained by conclusive proof, which error can- 
not possibly be. Knowledge also implies belief; an d 
therefore a truth which a man rejects, or does not be- 
lieve, is not known to him, however well it may be known 
to others, and even if he formerly believed it himself, on 
good grounds. 

2. We distinguish unknown truths from the known by 
terming the latter cognitions, which may be defined — 
truths known to be such. Intuitions and comprehen- 
sions may be termed immediate or direct knowledge, as 
we know them directly, without the intervention of any 
proof or process. The two faculties of Intuition and 
Comprehension may be designated by the common term 
Consciousness or Discernment / and truths known by 
it may be called discernments. These are accompanied 



Sec. 1.] Necessary Limits, &c., of Knowledge. 32 

with a direct knowledge of their certainty, so that they 
require no proof; and they may be said to be discerned. 
Inferences, being made known only by intermediate 
proofs and processes, may be termed mediate or indirect 
knowledge. 

Consciousness includes the knowledge which we neces- 
sai'ily have of the reality of all our present thoughts and 
their immediate objects, or those things of which we 
think. It is self-evident that we cannot think without 
knowing that we think, and that we cannot know unless 
there is something that we know. When we see, for ex- 
ample, there must be something that we see, and we 
necessarily know that we see. So when we feel, we nec- 
essarily know that we feel, and that there is something 
which we do feel. 

3. There is no necessity for our possessing compre- 
hending faculties, such as we actually possess, nor for the 
existence of the things comprehended. Thus some men 
cannot see, and the things which we see might have had 
no existence. Comprehensions may, therefore, be termed 
contingent truths : and those which are necessarily im- 
plied in them are properly classed under the same term. 
As these depend on contingencies, they are not necessa- 
rily true ; for a necessary connection between two things 
does not imply the existence of either, but only that if 
one exists, the other must exist. 

Another class of cognitions is, that which expresses 
certain properties or relations of things merely supposed 
or assumed, and having possibly no' actual existence. 
These may be called hypothetical truths. Such are, the 
properties of a machine which has yet no actual exist- 
ence, but is merely planned by the inventor, and conse- 
quences which have been proved to follow a certain 
course of conduct, which is only supposed, and has not 
been actually adopted. 

As inferences from intuitions are necessary truths as 
much as the original intuitions, both classes fall under 
that class of cognitions. Hence., necessary, contingent 
and hypothetical cognitions include all human knowl- 
edge. The first class comprises what must be ; the sec- 
ond, what actually was, is, or will be, though not neces- 
sarily ; and the third, what will be, if certain things are 
assumed or pre-supposed. 

These three classes of truths do not differ in respect 



32 Limits and Sources of Knowledge. [Chap. I. 

to certainty : all are equally certain, where they agree 
with the proper criterions, and we are liable to err in re- 
gard to each. Statements have been believed to be self- 
evident which are untrue, and fallacious mathematical 
demonstrations are by no means unknown, while, at the 
same time, contingent and hypothetical cognitions may 
be established conclusively, although this is frequently 
more difficult than the demonstration of a mathematical 
theorem. 

§ 2. Op the various Faculties by which Knowledge is acquired 
and retained. — Definition of Faculty. — Nature of Apprehension. 
— Knowledge acquired through Apprehensions. — Reasoning. — Na- 
ture of Remembrance. — On what dependent. — Similitudes, Ideas, 
Phantasms, and Prototypes. — Comprehensions. — Knowledge de- 
pendent on Remembrance. — Nature of Emotions, and what we 
know directly by them. — Nature and general laws of Attention. — 
Nature of Abstraction, and of Conception. — Notions and Imagina- 
tions. — Nature of Generalization. — Six things which necessarily 
exist in all Thinking. — Frequent Errors. 

By a Faculty is understood a power, capacity or sus- 
ceptibility of thinking, feeling or acting. Hence what- 
ever we do, we must have a faculty of doing, and what- 
ever we feel, we must have a faculty of feeling. We 
cannot, for instance, see without the power of seeing ; 
we cannot reason without the power of reasoning ; and 
we cannot feel, unless we are susceptible of feeling. 

That we see colors, hear sounds, and smell odors, are 
sure truths, whatever difference of opinion may prevail 
regarding the origin of such cognitions. The faculties 
by which we thus obtain immediate knowledge, through 
the influence of things external to the mind, are termed 
apprehending faculties or Apprehension, and the cogni- 
tions obtained apprehensions. They are all properly 
classed together here, since they resemble each other in 
depending on some impression made on a nerve, by 
means of which a corresponding impression is made on 
the mind. 

The knowledge thus obtained consists of sensations, 
or the pleasant and painful feelings which we experience, 
and perceptions, or that of which we are conscious, be- 
sides what we feel. Thus, when we view a green field, 
the green expanse which we behold is quite distinct from 
the pleasing or painful feelings which accompany this 
perception. 



X: 



Sec. 2.] Op the Faculties. 33 

As we know intuitively that certain truths necessarily 
imply others, we learn the existence and observable prop- 
erties of material and living beings by applying the fac- 
ulty of Intuition to our apprehensions. Those truths are 
not apprehended directly; but they are implied in on' 
apprehensions, and learned by means of reasoning o:i 
drawing necessary inferences, the faculty of Intuition, 
when thus applied, being termed Reason. Thus, when 
we view a tree, the eye perceives only extended colors : 
but, by observing all the phenomena, and drawing the 
necessary inferences, we find that there is a solid body 
without us, of a particular form, size, and color. 

In drawing inferences, we are not confined to what we 
have personally apprehended : for, by means of testi- 
mony, we learn the apprehensions of others ; and we can 
draw inferences from these as we do from things pri- 
marily apprehended by ourselves. Certain sounds and 
visible characters are found to denote certain things, by 
means of which we learn the thoughts of others. We 
determine what those sounds and characters imply, by 
the proper application of our faculties, as in other inves- 
tigations. 

While tracing inferences, we are frequently obliged 
to reason about things not apprehended at the time. 
Thus, in proving conclusions, it is generally necessary to 
refer to things which are not present to our senses, such 
as things previously seen, heard or proved. This is done 
by means of Remembrance, the faculty by which we know 
our former thoughts. 

If we carefully consider the phenomena of Remem- 
brance, we shall find that it is not a simple faculty, but 
that it depends on two things. If we view a tree, and 
then close our eyes, we may still discern a faint and fleet- 
ing likeness of it ; and we find that the same is true of 
all our apprehensions: and so all other thoughts, also, 
have their likenesses, after the originals have disappear- 
ed. These likenesses I term similitudes. They may be 
subdivided into two classes — ideas, or similitudes of 
apprehensions — and phantasms, or similitudes of other 
thoughts, besides apprehensions. The original of a si- . 
militude I term its prototype. Trains of similitudes pass 
spontaneously through the mind, according to certain 
laws ; and the simple faculty of discerning them I call 
Memory. Apprehensions, similitudes and all other things 
B 2 



- 

34: LnuTS axd Soukces of Knowledge. [Chap. I. 

directly discerned, except intuitions, are included under 
the general term comprehensions. 

When we consider the phenomena of similirtides, Intu- 
ition leads us to the conclusion that they all had their 
prototypes : for all other suppositions involve an absurd- 
ity, as we shall see hereafter. Thus, by means of Mem- 
ory and Intuition, we can know and reason about the past 
as if it were the present. The last alone is known im- 
mediately, in respect of all contingent truths, whose past 
and future are known only by their being necessarily 
connected with something present. 

On comparing the peculiarities of the various objects 
of thoughts, we find a large class which, unlike appre- 
hensions, is immediately independent of anything beyond 
the mind. These consist of similitudes and of feelings 
which differ widely from those of Apprehension, although 
remotely dependent on them. These are generally term- 
ed emotions / and they resemble apprehensions in being 
known solely by Consciousness. We know the existence 
and character of our feelings solely from experiencing 
them, and neither by intuition, by reasoning, nor by the 
testimony of others, although we may investigate their 
origin, laws and component elements, as in the case of 
other thoughts. They also directly teach us nothing but 
their own existence and nature. We feel nothing but 
our feelings : we cannot feel the truth of any assertion. 
Thus we cannot feel that the sky is blue, that Alexander 
the Great died at Babylon, that things equal to the same 
thing are equal to each other, nor that the three angles 
of a triangle are equal to two right angles. 

We attend to that of which we think ; and the power 
of doing so is termed attention. This is of two kinds. 
Spontaneous attention is that which is produced by some 
present feeling, without desire or effort ; and it is gener- 
ally proportional to the strength and vividness of the 
feeling ; but where these become intense, they nearly ab- 
sorb the attention, or make us overlook other present 
objects of thought. Voluntary attention is that which 
is produced by a desire or effort of the Will, directing it 
to something which we deem of consequence ; and it is 
generally proportional to the importance of the subject, 
according to our belief; but where we consider this very 
great, the subject may nearly absorb the attention, like 
strong feelings. The actual degree of attention is fre- 



Sec. 2.] Of the Faculties. 35 

quently the result of the two kinds operating simultane- 
ously, and proportional to their united amount: but it 
often depends on one alone. 

Attention is evidently not a distinct power of the 
mind, but merely a general name, to denote the exercise 
of our faculties with reference to particular objects of 
thought : and it is usually exerted with reference to sev- 
eral objects at the same instant^, During our waking 
state, we generally attend simultaneously to our appre- 
hensions and ideas. Thus, when we walk with a friend, 
we attend to the organs of motion and speech, hear his 
conversation, observe various objects around us, and at- 
tend to the subjects of conversation, so that we collect 
the sense of what he says, and form our own replies. 
But it is observable that the force of attention diminish- 
es as the number of objects simultaneously considered 
increases. 

When we discern different things at the same time, we 
have the power of concentrating the attention on some 
and overlooking the rest. Thus, while viewing a tree, we 
may confine our attention to the trunk, the branches, the 
leaves, or the blossoms ; and, with respect to the latter, 
we may consider their form, their odor, their color, or 
their position and arrangement. This faculty is termed 
Abstraction, which may be defined as that by which we 
fix the attention on particular objects of thought, and 
withdraw it from others, at pleasure, or as long as the 
object is present. In the case of apprehensions, the phe- 
nomena of course vanish when their causes are with- 
drawn ; but, with regard to similitudes, we may retain 
and consider them till mere weariness or exhaustion in- 
duces us to turn to something else. 

Abstraction is spontaneous where it results simply 
from the pleasure or pain of a particulaivfeeling, and vol- 
untary where we voluntarily limit the attention, for some 
pui-pose, which is discovered by the aid of Reason. 
Hence the exercise of voluntary abstraction is dependent 
on the latter faculty. Yet it is a distinct power, which 
is requisite in order to discover the peculiar and general 
properties of the various objects of human research. 

Besides observing the phenomena of Comprehension, 
and drawing inferences from them, we can modify the 
simple elements, and combine them into a new whole, 
different from any which we ever comprehended. Thus, 



36 LnnTS A2TD SOUECES OF EJN'OWXEDGE. [CHAP. I. 

ive can think of a small horse from having seen a large 
one, or of a circle being elongated into an ellipse, or of 
the half of it, without the rest, or of a green horse with 
an ox's head. The combination may be either of the com- 
prehensions or of the modifications previously thought of, 
or of the two blended, as in the case of the last instance 
just mentioned, in which case there is a double exercise 
of the same faculty. VTe may afterwards modify and re- 
combine the combination, and so on, without any definite 
limit, except what arises from the greater difficulty of 
the new combinations, on account of their greater com- 
plexity. 

This faculty we term Conception, and the thing thonght 
of, a conception. If this be of something not described 
nor known, we term it an imagination : if it be of some- 
thing described or represented to us by others, we term 
it a notion. Thus, an inventor imagines something new, 
and a person forms a notion of a plant or an animal from 
a description. Conception, when employed in imagin- 
ing, is termed Imagination : but it is essentially the 
same throughout, both in its nature and its processes. 

"When we compare several objects, we often perceive 
that, although they greatly differ in some respects, yet 
they have certain properties in common. Thus, the sky 
and the ocean are both Hue; flint, iron, and diamond are 
all hard ; water, oil of turpentine, and alcohol are all 
liquid '• and oxygen, hydrogen, and nitrogen are all gas- 
eous bodies ; the planet Venus revolves round the Sun, 
and so does Mars, &c. TVhen we thus note or ascertain 
a common property of several things, we are said to gen- 
eralize ; and the knowledge obtained is rendered perma- 
nent and available by means of general terms, or words 
that express the common property, wherever it exists. 
In this process there is no new faculty employed, but 
only several of those already described. 

In all thinking there necessarily exist six distinct 
things — (1) that which thinks, or the mind — (2) the fac- 
ulty by which it thinks — (3) the thought, or some act or 
exercise of the faculty — (4) the object of the act, or that 
which is discerned, known, believed or supposed — (5) a 
knowledge of the reality both of the act and of its imme- 
diate object — and (6) something which originates or 
causes the act, which may be either in the rnind or with- 
out. Thus, when we see, there are — (1) the mind, that 



Sec. 3.] Of Propositions. 37 

sees — (2) the faculty of vision — (3) an exercise of this 
faculty — (4) the thing seen, or the colors — (5) a knowl- 
edge that we think and see these colors — and, (6) the 
cause of our seeing them, which is, the action of rays of 
light on the retina. 

Various errors have arisen from confounding several 
of those things with each other, which happens the more 
readily because they are designated by the same term. 
A common instance is, confounding apprehensions with 
those qualities of substances which cause them, as when 
it is said " I feel the heat of the fire." The confusion 
becomes evident from the difficulty which is generally ex- 
perienced in distinguishing the perception of color from 
the objective reality which causes it. We do not readi- 
ly believe that there can be nothing either in or on the 
colored substance which in the least resembles its color, 
any more than there can be anything in a bell resembling 
its sounds. A similar, but much less common, error is, 
confounding thought with the thinker. The former is 
only an act of the latter, and totally different from its 
essence or substance, of which it cannot possibly form a 
part. 

§ 3. Op Peopositions. — Definition of Propositions. — Subject and 
Predicate. — Expression of a Proposition. — Converse, contrary, and 
contradictory of a Proposition. — Identical Propositions. — Import- 
ant property of these. — Simple, Alternative or Disjunctive, and 
Complex or Compound Propositions. — Absolute and Conditional 
or Hypothetical Propositions. — Affirmative and Negative Proposi- 
tions. — Universal, General, Particular or Indefinite, and Individual 
or Singular Propositions. — Frequent ambiguities. — Various forms 
of Propositions. — Caution. — Combinations. 

Everything affirmed or denied is expressed by a prop- 
osition, which is, an assertion of a truth, assumption, sup- 
position, belief or opinion : and it is either expressed in 
words or simply declared by the mind. It may refer to 
the past, the present, or the future, or to any two of them, 
or to all time. 

Every proposition necessarily consists of at least two 
parts, the one relating to the thing of which something 
is said, or the subject, and the other, to what is said of it, 
which is termed the predicate. Thus, in the proposition 
"just men abhor deception" the first two words are the 
subject, and the latter, the predicate. These are essen- 
tial parts of every proposition, since, in every assertion, 



38 Limits and Sources of Knowledge. [Chap. I. 

there must be something of which we assert, and some- 
thing which is asserted regarding it. The subject and 
predicate may each consist of a single term, as " John 
sleeps," or of a long clause, as " every one who desires 
the welfare of his country, will cheerfully submit to pri- 
vations, for the public good, during times of general dis- 
tress;" or each part may consist of several connected 
clauses, as " the true patriot, and the wise and upright 
statesman, will not be turned from the path of duty,~ei- 
ther by the threats of the powerful or the clamor of the 
multitude." (2) 

The proper expression of a proposition requires at least 
two words, one denoting the thing spoken of, and the 
other, what is said of it. The common idiom of a lan- 
guage may, indeed, require only one word, as in the Lat- 
in expression pluit, (which is equivalent to "it rains:") 
but, in all such cases, some second word is understood. 
Thus the preceding verb has some nominative under- 
stood, such as Jupiter, or Deics (God). So the English 
expressions yes and no are only abbreviations for a re- 
sponsive repetition of the terms of the question. 

The converse of a proposition is one in which the sub- 
ject is asserted of the thing predicated, so that subject 
and predicate change places. Thus — " those who abhor 
deception are just men," is the converse of the first ex- 
ample given above. The contrary of a proposition is 
one which predicates the contrary attribute of the same 
subject. Thus — '•'■John is weak?"* is the contrary of u Joh?i 
is strong." By contrary attributes are meant those which 
are most unlike, of the same class, as good and bad, wise 
and foolish, hard and soft, high and low, black and white, 
light and heavy. The contradictory of a proposition is 
one which denies of the subject the attribute which the 
former asserted. Thus — "John is not strong" is the 
contradictory of " John is strong." 

An identical proposition is one which predicates the 
subject of itself, or whose subject and predicate are iden- 
tical, as " a man is a man" — " azote is another name for 
nitrogen" — "Philip was the father of Alexander" — "Lon- 
don is the capital of the British Empire." To this class 
of propositions belong all verbal definitions, or those 
which explain the signification of terms, provided that 
they are accurate — and it is an evident property of the 
whole class that, if the original proposition is true, so is 
the converse. 



Sec. 3.] Of Propositions. 39 

A simple proposition is one which attributes a single 
property to a single thing, as " John died." One which 
attributes one or other of several properties to a sub- 
ject, is termed alternative or disjunctive, as " John is ei- 
ther in London or in Paris or in New York." A com- 
plex or compound proposition attributes various proper- 
ties to the same or to different things, as " man is mor- 
tal, and yet frequently forgets his mortality" — "John 
died yesterday, and James died to-day." Propositions 
of this kind consist of several simple propositions united, 
into which they may be resolved. On the other hand, 
where the different things contained in a compound prop- 
osition form one whole, and the same thing is attributed 
to every one of them, the compound proposition may 
be expressed simply. Thus, the compound proposition 
" John is a descendant of Adam ; Mary is a descendant 
of Adam, etc." is tantamount to " All mankind are de- 
scendants of Adam." 

An absolute or unconditional proposition affirms the 
predicate absolutely, without any condition, as " All men 
are mortal." A conditional or hypothetical proposition 
predicates only upon some condition or supposition, as 
"If report be true, all men are mortal" — "Although he 
should do that, he would gain nothing by it." 

An affirmative proposition asserts the predicate of the 
subject, as "John is dead." A negative proposition de- 
nies it, as " John is not dead" — " No man is mortal." 

A universal proposition predicates of all the individ- 
uals of a class or all the parts of a whole, as " All men 
are mortal" — "No matter is unextended." A general 
proposition predicates of most of a class or whole, as 
" Most men are rational" — " Carbonic acid is generally 
gaseous." A particular or indefinite proposition affirms 
or denies of a small or indefinite part, as " Some men are 
wise." A singidar or individual proposition predicates 
of a single individual or part of a whole, as "John thinks" 
— " This piece of wood is brittle." 

The classes of propositions defined in the preceding 
paragraph are frequently expressed in such a manner as 
to render the extent of the subject ambiguous or doubt- 
ful. Thus, in the proposition " Man is mortal," the sub- 
ject may mean either "every man" or only "Most men." 
So, "Men say so" — may mean "All" or "Most" or only 
" Some men." Such ambiguities have been a frequent 
occasion of error. 



40 Lucres axd Soueces of Knowledge. [Chap. I. 

Propositions may frequently be varied in the form of 
expression, so as to bring them under a different class, 
without in the least changing their signification. Thus, 
the conditional proposition " If report be true, all men 
are rational," is equivalent to the absolute proposition 
" It is reported that all men are rational," or, " The ra- 
tionality of all men is reported." So the affirmative prop- 
osition " All men are mortal" is tantamount to the nega- 
tive proposition " Xo man is immortal ;" and " John is 
not dead" is equivalent to " John is alive." As the nega- 
tive of an attribute is tantamount to the affirmative of its 
contradictory, every negative proposition may be con- 
verted into an equivalent affirmative. Hence it appears 
that, in examining propositions, we should regard their 
real signification or import, rather than their form. 

The several kinds of propositions may be combined 
with each other indefinitely. Thus, the proposition " If 
John did that, he is either a knave or a fool," combines 
the conditional and alternative forms. So we may com- 
bine the conditional with an affirmative or negative, sim- 
ple or compound l universal or particular, and so forth. 

§ 4. Op Probability. — Definition of Probability. — (1) Probabilities 
founded on previous experience regarding the concomitance of cer- 
tain properties. — What these imply. — When they become certain- 
ties. — Principle of Reasoning. — (2) Probabilities founded on what 
we know has happened in cases apparently similar. — Principle of 
Eeasoning. — Why we often err. — Connection between Agencies 
and their Results. — (3) Probabilities based solely on what must 
happen. — Distinction between these and the preceding classes. — 
Source of frequent error, and mode of avoiding it. — (4) Probabili- 
ties founded on the known connection between Causes and Effects. 
— Use of Experience. — Common error. — (5) Probabilities based on 
actual investigation of proof. — Distinction between Probability and 
Certainty. Principles of Reasoning in all cases of Probability. — 
Influence of individual Experience. — Uses of Probability. — Cir- 
cumstances in which it exists, and to what generally proportional. 
— Resultant Probabilities. — Means of ascertaining their value. 

A probability is, a proposition implying facts which 
tend to prove, but which do not absolutely prove, that it 
is a truth. Probabilities are of various kinds, the most 
common of which are included under one or other of the 
five following classes. 

1. In comparing two things, we frequently observe 
that they possess many obvious properties in common ; 
and although there is no proof that they possess unob- 



Sec. 4.] Op Probability. 41 

served properties in common, yet experience informs us 
that this has been found to hold true, in similar instan- 
ces ; and this we indicate by saying that such improbably 
the case. Here the probability implies, not only that a 
proposition may be time, but that it has actually been 
found true, in similar cases ; and the probability is great- 
er or less, according as the cases in which the unobserved 
attributes were afterwards found to be common, are more 
or less numerous, or as the resemblance is more or less 
extensive. 

Of this kind is the probability that a certain effect 
will follow from an agency similar to one whose effects 
are known, that an effect has been produced by a cause 
known to have produced similar effects, and that two or 
more similar phenomena have similar causes, antecedents, 
concomitants or effects. Other cases are, that the testi- 
mony of a person of doubtful veracity or a stranger, re- 
garding some unknown subject, is true, that a man will 
continue to act as he has hitherto done, in apparently 
similar circumstances, that a certain phenomenon has 
been preceded by its usual antecedent, or the reverse, 
and that a newly discovered species will be found simi- 
lar, in unobserved attributes, to known species to which 
it bears a general resemblance. 

This class of probabilities is based on the self evident 
principle that where the determining conditions or agen- 
cies are the same, the results will be the same. When- 
ever we ascertain that the conditions or agencies are act- 
ually the same, in two or more cases, the results must be 
the same, and probability gives place to certainty, as the 
former exists only where we know but of a partial simi- 
larity of the determining conditions. 

2. Results are found to vary, in cases apparently simi- 
lar, while the previous variations are known. Thus, if a 
person has succeeded in effecting a certain result, by the 
same apparent means, in seven cases out of ten, we say 
the probability, or chance of his succeeding, in the next 
attempt, is seven tenths, and of his failing, three tenths, 
the cases being all alike, so far as is known. We reason 
on the self-evident principle that results must follow as 
they have done, in the same circumstances. But there 
is frequently no means of ascertaining that the several 
cases are, in reality, perfectly alike ; and hence the future 
results often turn out differently from what the probabil- 



42 Limits and Sources of Knowledge. [Chap. I. 

ity indicated. Such probabilities are evidently propor- 
tional to the ratio which the favorable cases bear to the 
whole. 

Whatever affects the agencies concerned in producing 
results, will affect these in a corresponding degree. 
Thus, greater attention to the laws of health, in a com- 
munity, increases the probability that a person of a cer- 
tain age, taken at random, will live so many years ; and 
greater temperance among seamen will lessen the chances 
that a ship will be lost at sea. The probability varies, 
in such cases, as the agencies which determine the re- 
sults vary. 

3. One or other of several results must happen, and 
we know no reason why one should happen more than 
another. Thus, as a certain day must be fair or foul, we 
say it is an even chance that it will be fair. Here the 
probability varies inversely according to the number of 
possible results, being greater as these are fewer, and 
conversely. These differ widely from the preceding- 
kinds of probability : for here our expectations are based 
solely on what must happen, independently of any knowl- 
edge as to what has happened, and, unless experience 
prove the contrary, there may be unknown agencies 
which will interfere with the expected results. Thus, if 
a certain time of the year is generally fair, there is more 
than an even chance that the day will be fair, and con- 
versely. It is, therefore, very unsafe to act on the as- 
sumption that certain results will follow, where we are 
ignorant of what has happened, in circumstances similar 
in reality, and not merely in appearance. 

4. A certain change must have resulted from one or 
other of several causes, or a cause must have produced 
one or other of several results, and we have no reason to 
decide in favor of one agency or result more than anoth- 
ei\ Thus, a disease must have arisen from some viola- 
tion of the laws of health, or from some original unsound- 
ness of constitution, or from both combined ; and, there- 
fore, we might say, where we know nothing regarding 
the person affected, the chances are one third, or one to 
three, that it has proceeded solely from an unsound con- 
stitution. The degree of probability varies with the num- 
ber of causes or results. But experience is here pecu- 
liarly requisite, since we cannot generally decide, with 
certainty, as to the number of causes which may have op- 



Sec. 4.] Of Peobability. 43 

erated, and we are liable to substitute mere suppositions 
instead of the real agencies concerned in producing the 
results. Many baseless scientific theories have origin- 
ated in this manner. Experience frequently alters ab- 
stract probabilities of this kind, so that the actual proba- 
bility is the result of a combination of various elements. 
Thus, in the case just mentioned, when we come to know 
the extreme frequency of violation of the laws of health, 
and the comparatively rare cases in which original con- 
stitutional defects are the sole cause of disease, we shall 
find that the chance of such a defect being the sole cause 
of a disease, instead of being one to three, is not one to 
three hundred. 

With regard to the results which a certain agent may 
be expected, to produce, we generally reason more on 
our previous experience than on necessity ; and we are 
apt to assume a degree of similarity, in two cases, which 
does not actually exist, as when it is assumed that a med- 
icine will produce one or other of two results on a pa- 
tient, because it has done so in other cases apparently 
similar, although the former may differ in several import- 
ant peculiarities. 

5. The proofs which support a certain proposition have 
been examined, and we infer that it is true ; but the ex- 
amination has not been so close or thorough as to ex- 
clude the possibility of mistake. Here the probability 
varies with the degree of care employed in the examina- 
tion. If it has been conducted by others, and not by 
ourselves, the degree of probability will vary with their 
character, being higher or lower, according as they are 
careful investigators and faithful relators or the reverse. 

When the subject has been examined in such a man- 
ner as to leave no possible room for any error, the con- 
clusion is certain, and not merely probable. But we can 
never safely assume this regarding the conclusions of oth- 
ers, unless we have properly tested them, as we cannot 
know that their examination is of that character. They 
furnish only probabilities, which vary with the character 
and circumstances of our informants. 

In this class of cases, we reason on the self-evident 
principle that the probability of a proposition varies ac- 
cording to the nature of the proof by which it is sus- 
tained. 

From its nature, no degree of probability can amount 



44 Limits and Soukces of Knowledge. [Chap. I. 

to a certainty ; nor does the one pass by insensible gra- 
dations into the other. "When a proposition has been 
found to be certainly true, this immediately places it in 
a class widely removed from probabilities. We must 
beware, however, of adopting any probability as a cog- 
nition until we have obtained conclusive proof.(3) 

In every case of probability we reason upon self-evi- 
dent principles, as in cases where we arrive at certainty ; 
but, in the former, we reason from evidences which are 
incomplete or inconclusive, and consequently the results 
partake of the nature of their sources, whereas, in the 
latter, the foundations are known truths, and, therefore, 
if our arguments or proofs are legitimate, our conclusions 
are absolutely true. 

Men are apt to base their views of probability mainly 
on their individual views and experience, while they 
either reject or do not know the experience or knowl- 
edge of others: and hence the same proposition often 
appears very probable to one and extremely improbable 
to another. Thus, Herodotus disbelieved the statement 
of the Phoenician mai'iners, who had sailed round Africa, 
that, dui-ing part of their voyage, the sun rose on the 
right hand when they faced its position at noon, whereas 
a person who possessed a more extensive knowledge of 
Astronomy would consider such a statement highly prob- 
able, if not a matter of course. 

Although probability never amounts to knowledge, 
yet it is often of great consequence, both in scientific in- 
vestigations and in the ordinary business of life. In the 
former case it acts as a guide and stimulant, and many 
truths would never have been discovered, had there been 
no previous indications pointing to a certain conclusion. 
It guides us in establishing the proposition in question, 
by pointing out what is wanting, in order to that end ; 
and it stimulates to investigation by showing that more 
or less of the task is already accomplished, and thus prom- 
ising important results for comparatively little toil. It is 
also of great value in many of the ordinary affairs of life ; 
for it enables us to determine the most eligible course, 
where certainty is unattainable. 

Probability exists only where we have partial knowl- 
edge, and are at the same time ignorant on some points 
which we require to know, in order to possess certainty. 
Where we are totally ignorant, we know of no probabil- 



Sec. 5.] General Criterion of Truth, &g. 45 

ity ; and where our knowledge is sufficiently extensive, 
the probability gives place to certainty. The degree of 
probability is generally proportional to our knowledge 
of what is requisite to be known, in order to arrive at 
certainty. 

The probability of the truth of a certain proposition 
is often the resultant of several probabilities combined, 
every one diminishing or increasing the preceding, ac- 
cording as it is discordant or accordant. Thus, the prob- 
ability that a certain testimony is true, may be the re- 
sultant of the probability that the witness knows the 
truth, and that he asserts what he believes. The prob- 
ability of his knowing the truth, again, may be the re- 
sultant of several remoter probabilities, such as his means 
of ascertaining the truth, the use he has made of them, 
the tenacity of his memory, and the relation between his 
statements and those of others who possessed the means 
of forming a right judgment on the subject. 

The resultant of several accordant and independent 
probabilities is generally proportional to their total 
amount ; and where there are discordant probabilities, 
the resultant generally varies with the difference between 
the amount of the former and that of the latter kind. 

The resultant of connected probabilities, or probabil- 
ities of probabilities, generally varies as the product of 
the factors expressing the value of each. Thus, if it is an 
even chance that a witness correctly knows what he re- 
lates, and a similar chance that he reports correctly what 
he knows, the probability that his statement is true, is 
only as one to four. In such cases every new probabil- 
ity introduced may diminish the resultant. 

§ 5. General Criterion of Truth, and Immediate Source of 
Error. — Apprehensions real, and why. — Only possible sources of 
Error. — How these may be avoided. — Distinctions between Appre- 
hensions and Ideas. — All other Comprehensions like the former. — 
How we ascertain whether a proposition is self-evident. — Requisites 
to the validity of inferences. — How these are distinguishable from 
Intuitions. — How inattention occasions error. — Expression of the 
general criterion of Truth, and the immediate source of Error. — 
How erroneous Belief may be avoided. — Its uniform concomitant. 
Belief includes Knowledge and Opinion. 

Not only are we directly conscious of our apprehen- 
sions, but we know intuitively that it is impossible for 
any being to believe that he thus apprehends when, in 



46 LiiriTS axd Sources of Knowledge. [Chap. I. 

reality, he does not. Thus, when I view the clear sky, 
I know immediately that I perceive a hlue expanse ; and 
when I feel pain, I have a direct and unerring knowledge 
of the reality of my sensation. This holds equally true 
of every sensation and perception. 

It is self-evident that no apprehension can exist with- 
out attention. Thus, when the attention is completely 
absorbed by other thoughts, a person exposed to a freez- 
ing temperature can have no sensation of cold, and if a 
clock should strike near him, he cannot hear it. It is 
common to have apprehensions which are immediately 
forgotten, because they excite very little attention : but 
it is impossible for us to apprehend without any atten- 
tion whatever to the thing apprehended ; otherwise we 
should be conscious of that of which we were not con- 
scious, or think what we did not think. 

The only possible sources of error, on this point, are, 
mistaking one apprehension for another, or for a simili- 
tude : and it requires only a moderate degree of atten- 
tion to avoid such errors, since the various kinds of ap- 
prehensions are palpably different from each other, and 
similitudes are much fainter and under the control of the 
Will. Thus, there is no danger of mistaking a soimd for 
a color, or even the smell of a rose for that of tobacco. 
So it is very easy to distinguish the mere idea of the 
Moon from actually seeing it : for not only are our organs 
of vision very differently affected in the two cases, but it 
requires no effort of the "Will to continue the apprehen- 
sion, whereas the mere idea speedily gives place to some 
other thought, unless we retain it by a conscious effort 
of the Will. On the other hand, we may discern the idea 
at pleasure, whereas the apprehension is dependent on the 
presence of its cause, and ceases when that disappears. 

The reality of other comprehensions admits of as little 
rational doubt as that of apprehensions. Thus, when I 
discern the idea of a tree, I am as conscious of the real- 
ity of the discernment as if I viewed the tree. Atten- 
tion is here even more requisite than in the former case, 
as there is no external object to excite the comprehen- 
sion. 

We are liable to mistake an apprehension for its idea ; 
but the peculiarities which distinguish the former are so 
obvious that it requires only a little attention to avoid this 
error, The same remark applies to the distinctions be- 



Sec. 5.] General Criterion op Truth, &c. 4V 

tween the other kinds of comprehensions. Thus, an idea 
is distinguished from a conception by the former being 
spontaneous, while the latter is the result of a voluntary 
effort, and less vivid ; and it is distinguished from a 
phantasm by our recollecting the latter's origin, and its 
exhibiting the peculiarities of its prototype. We avoid 
error here precisely as in the case of apprehensions and 
ideas. 

Hence we may see that attention will enable us to 
avoid errors in regard to all comprehensions, and that 
these must arise from inattention, as in the case of appre- 
hensions. 

In order to determine whether a proposition is an in- 
tuition or self-evident truth, we have only to consider it 
with attention : for the very nature of an intuition is, 
that the attentive mind discerns its necessary truth, and 
its falsity to be an impossibility. We may first consider 
whether it is discerned to be self-evidently and neces- 
sarily true ; and if we have any hesitation, it may be re- 
moved by considering whether its contradictory, or the 
proposition denying its truth, is possible : for if we have 
the evidence of consciousness either way, that suffices. 
A proposition which must necessarily be true, and one 
which cannot possibly be false, are evidently both enti- 
tled to equal and perfect credence, and free from the pos- 
sibility Of a rational doubt regarding their truth. 

Our comprehensions and intuitions are often intuitive- 
ly known to imply cognitions entirely different from 
themselves ; these may be known, in the same way, to 
imply others, and so on, without any definite limit. The 
existence of A, for example, may necessarily imply that 
of B, which may prove that of C, and so on. The num- 
ber of these intermediate cognitions is a matter of no es- 
sential importance. All that is necessary, in order to es- 
tablish the truth of the last inference, is, that the original 
proposition be true, and that there be a self-evident con- 
nection between every cognition and the proposition 
which immediately follows. This can be ascertained by 
attentively considering whether one proposition neces- 
sarily implies that which is immediately founded on it, 
or deduced from it ; for if it does, the connection becomes 
self-evident upon an attentive consideration and compari- 
son of both. 

Owing to the extreme rapidity of thought, we are lia- 



48 Limits akd Sources of Knowledge. [Chap. I. 

ble to mistake inferences for intuitions or comprehen- 
sions, since we may overlook the processes by which we 
arrived at them : but a proper degree of attention will 
always show their true character ; for the distinction be- 
tween discernments and inferences is as easily discover- 
ed as that between intuitions and apprehensions. 

Inattention occasions error by its leading us to over- 
look differences, or to draw immaterial distinctions, or by 
concealing something from view altogether. There is no 
other possible way in which we can be led into error : 
for we can mistake one thing for another only by over- 
looking differences or drawing unimportant or irrelevant 
distinctions ; and if everything which concerns the sub- 
ject is clearly before the attentive mind, there can be no 
false or unwarrantable inferences. 

Thus it appears that the general criterion of truth is, 
the evidence of attentive Consciousness, either direct or 
indirect. The former tests comprehensions and intui- 
tions, and the latter, inferences. It also appears that in- 
attention is the sole immediate source of erroneous opin- 
ions, which all spring from our not being sufficiently at- 
tentive to those things which must be carefully consid- 
ered, in order to attain to truth. 

That we often believe what is false, does not in the 
least prove that we can never certainly know whether 
any proposition is true. Wherever our belief is errone- 
ous, there must have been a want of attentive considera- 
tion of one or more of the circumstances necessary to 
form a correct opinion : for it is obvious that, if the orig- 
inal assumption cannot be false, and that it necessarily 
implies a certain inference, the latter must be true. 
There is a certain number of steps in every process, ev- 
ery one of which we can consider with the greatest at- 
tention ; and hence we can know whether we have given 
the proper degree of attention to every point which 
ought to be considered. 

Where there is any room for doubt or uncertainty, as 
to whether we have sufficiently attended to every point, 
we are not warranted in assuming the proposition in 
question as established. But wherever we know that 
this has been done, the proposition cannot be false. In 
every case of erroneous belief, we may discover a want 
of due attention on one or more points. Thus, in dream- 
ing, insanity and delirium, similitudes are taken for pro- 



Sac. 1.] Nature, &c, of Reasoning. 49 

totypes, because characteristic peculiarities are overlook- 
ed. In such cases, indeed, there is hardly an attentive 
consideration of anything, but merely a train of ideas or 
apprehensions passing through the mind, accompanied 
with those thoughts which they immediately excite. So, 
when we mistake a false inference for an intuition, we 
cannot have carefully considered whether the proposition 
is really intuitive. 

Belief includes all that we believe, or take to be true, 
whether true or false. It may be subdivided into faioiol- 
edge and opinion. Knowledge is, belief based on atten- 
tive consideration and the evidence of consciousness at 
every step, so that there is no room for error, and no 
reasonable ground for doubt or disbelief. Opinion in- 
cludes all other belief, whether correct or not. - m 



CHAPTER H. 

OP REASONING. 

§ 1. Nature, General Principle, and Expression of Reasoning. 
— Two kinds of Knowledge obtained by means of Intuition. — Na- 
ture and definition of Reasoning. — Identity of the process, in every 
ease. — Its importance. — General principle of Reasoning. — Extent 
of its application. — Definitions of Syllogism and its parts. — Differ- 
ent modes of expressing Syllogisms. — Best mode. — Part frequently 
suppressed. — When it ought to be expressed. — Reason for a thing. 

The knowledge obtained by means of Intuition is of 
two kinds, immediate and mediate. The former regards 
the self-evident and necessary properties and relations of 
things: the latter consists of inferences which are neces- 
sarily implied in other propositions. 

We frequently know by Intuition that if one thing is 
true, another thing must be equally true. Thus, if I know 
that it is full moon, I know, with perfect certainty, that 
it is not new moon. Here is an act of Reasoning, which 
is, simply drawing necessary inferences, or finding out, by 
means of self-evident truths, propositions that are neces- 
sarily implied in others. To reason is, to discern intui- 
tively that one thing necessarily implies another, or that, 
if the former is true, the other is necessarily and inevita- 
bly true, and cannot by possibility be false. That such 
is the nature of all valid reasoning appears, not only from 



50 Of Reasoning. [Chap. n. 

an analysis of the process, but from the fact that it can- 
not possibly be otherwise. There is no possible means 
of knowing anything indirectly, except by discerning 
that it is necessarily implied in something which we 
know directly. (4) 

In all sound reasoning the thing implying is compared 
with the thing implied ; and the necessary implication is 
discerned intuitively. The process may, indeed, be fal- 
lacious, and the supposed inference may not, in reality, 
be necessarily implied : but this is never the case in valid 
or legitimate reasoning, which is what we mean when we 
speak generally ; and, even in fallacious reasoning, the in- 
ference is supposed or professed to be necessarily im- 
plied. 

Thus it appears that Reason, or the faculty of reason- 
ing, is only Intuition, applied to discover mediate knowl- 
edge, or to find out necessary consequences, by means of 
self-evident truths, and that the cognitions implied in our 
apprehensions are as dependent on Intuition as on Ap- 
prehension. 

Whatever may be the subject, the reasoning process is 
identical in all cases: it is, always, simply discovering 
that one thing necessarily implies another. But it is of 
the utmost importance, because it is requisite to the ac- 
quisition and retention of all mediate knowledge. 

The general principle of all reasoning is, that wherever 
one thing necessarily implies another, the existence of the 
former conclusively proves that of the latter, the neces- 
sary implication being always discerned by Intuition. It 
maybe otherwise expressed thus: wherever one proposi- 
tion necessarily implies another, the latter is true if the 
former oe true. The conclusiveness of such inferences is 
evidently independent of the actual truth of the. imply- 
ing propositions : we may draw necessary inferences from 
a proposition that is merely assumed or supposed to be 
true, as well as from one which actually is so. This pro- 
ceeding is frequently of the utmost importance, although, 
in order to avoid error, we must distinguish it from 
those cases in which the implying propositions should be 
actual truths. 

A single act-of reasoning is called a syllogism. Every 
syllogism necessarily consists of three parts, and no more, 
which may be designated as follows — (1) Xhz premise, or 
implying proposition — (2) the inference, or proposition 



Sec. 1.] Nature, &c, of Reasoning. 51 

necessarily implied — and (3) the connective, or self-evi- 
dent truth by which we know that the inference is nec- 
essarily implied in the premise. (5) 

A syllogism may be expressed in various ways, as its 
parts may be differently expressed or arranged. The 
connective may be expressed in a more or less general, 
or in a particular form ; and the other parts are, of course, 
susceptible of the usual variety of expression. The fol- 
lowing may serve as an example of these variations. 

1. Everything that thinks, exists : (Connective) 
I think ; (Premise) 
Therefore I exist. (Inference) 

2. I think ; therefore I exist : for whatever thinks ex- 
ists. 

3. I know intuitively that if I think I gxist : but that I 
think is a matter of immediate consciousness ; therefore 
I exist. 

4. I exist : for I think ; and whatever thinks exists. 

5. It is self-evident that whatever thinks, exists : there- 
fore I exist ; for I am directly conscious of thinking. 

6. I am immediately conscious of thinking ; and what- 
ever thinks must exist : therefore I exist. 

7. I certainly exist: for every being that thinks ex- 
ists ; and I know, by direct consciousness, that I think. 

In stating a syllogism, the best arrangement is that 
which exhibits most clearly the necessary connection be- 
tween the premise and the inference ; and there is often 
little to choose, between several modes. The connective 
is frequently suppressed in discourse, because the mind 
can generally supply it, as it is suggested or rendered 
obvious by comparing the premise and the inferences. 
Thus the above syllogism may be expressed " I think : 
therefore I exist." The premise, also, is, in many cases, 
not distinctly expressed, as it is presumed to be well 
known to the party addressed, or to be apparent from 
the preceding assumptions. So the inference is often 
omitted, where it is presumed to be well known, and the 
question only regards the proof. But wherever there is 
any difficulty or doubt, every part of the syllogism should 
be expressed. 

Where a premise is acknowledged to be true, it may 
be assigned as a proof of the inference ; and, in such 
cases, it is frequently termed the reason for it. 



52 Of Reasoning. [Chap. II. 

§ 2. Special Principles of Reasoning. — Definition and Nature of 
these Principles. — Their number. — (A) Definition and two gener- 
al expressions of Truisms. — Eight principal modifications of these. 
— (B) Seventeen principles relating to duration and extension. — 
(C) Forty-seven principles relating to abstract quantity. — (D) Def- 
inition of Being, and of various kinds of Beings. — Necessary and 
contingent properties. — Seventeen principles regarding the necessa- 
ry properties of substances in general. — Motion, Force, and Change. 
— Necessary property of Inanimate Beings. — Six principles regard- 
ing the necessary properties of Living Beings. — Thought. — Belief. 
— (E) Twenty principles regarding Determining Conditions and 
Agencies in general. — Causes and Effects. — How these are distin- 
guished from uniform Antecedents and Consequents. — Nine prin- 
ciples regarding Desires and Volitions. — (F) Eighteen principles 
of Inclusion and Exclusion. 

The special principles of reasoning are, those self-evi- 
dent and universal truths which are essential to reason- 
ing, and which we may rightly employ either as premises 
or connectives, in any argument or investigation. As all 
reasoning is only an application of Intuition, and intui- 
tions are the only self-evident and universal truths that 
we can know, it follows that these are the only legitimate 
principles of reasoning. A complete enumeration of them 
is neither practicable nor desirable, since their number is 
indefinite, and many of them are of very little use: but 
the more important of them are stated under one or oth- 
er of the following heads. 

A. Truisms. 

A truism is a proposition in which the predicate or a 
part of it, is asserted of itself, as — " a man is a man," and 
— " a Frenchman is a man." 

The general formulas, or expressions, of all truisms are, 
that a thing is equivalent to itself, and that every part of 
a thing belongs to it. These are susceptible of innumer- 
able modifications, of which the following are among the 
principal : 

1. A thing is not different from itself. 

2. Different things are not the same thing. 

3. A whole is equivalent to all its parts. As " all the 
parts" are the same as "the whole," this expression is 
the same as saying that a whole is equivalent to itself. 

4. Incompatibilities cannot coexist. This is only say- 
ing in other words that things which cannot coexist can- 
not do so. What these are, must be learned from other 
sources. 



Sec. 2.] Special Principles op Reasoning. 53 

5. Propositions which have the same amount and kind 
of proof, are equally credible. Hence, if one of such prop- 
ositions is unproved, all are unproved ; if one is estab- 
lished, all are established ; and if one is believed, all are 
equally entitled to belief. 

6. The character of a proposition is identical with that 
of others tantamount to itself. Therefore the former is 
true, false or doubtful, according as the latter have been 
found to possess any of these properties. This principle 
enables us to vary the forms of expressions without al- 
tering the signification, and to combine many proposi- 
tions into one, which is equivalent to the whole of them 
taken together. For it applies equally to cases where 
one proposition is tantamount to another, and to those 
where it is equivalent to several, which it comprises. 

V. Every proposition whose predicate correctly ex- 
presses the thing denoted by its subject, is necessarily 
true ; and so is its converse. If azote denote the same 
substance which is otherwise termed nitrogen, it must be 
true that " azote is nitrogen," and equally true that " ni- 
trogen is azote." So if it be true that " London is the 
capital of the British empire," it is equally true that "the 
capital of the British empire is London." 

8. Every proposition which declares that a part of 
the subject belongs to it, is necessarily true. Thus, " a 
Frenchman is a man" — "a horse is a quadruped," and 
" an eagle is a bird." 

B. Principles relating to Duration and Extension^ or 
Abstract Time and Space. 

1. Duration and extension necessarily exist. 

2. They are immutable, and independent of every other 
thing. 

3. Every change occurs in time and space. 

4. All their attributes are unaffected by any other 
thing, or by any change. The parts of duration succeed 
each other uniformly, beyond the power of control, and 
can neither be accelerated nor retarded. So, extension 
is unaffected by the bodies that may occupy portions of 
it, or pass through it. 

5. Both are incapable of either motion or thought. 

6. They cannot originate any change or motion. 

7. They are imponderable, or without weight. 

8. They cannot affect any of our senses. We cannot 
feel, taste, smell, see, or hear either time or space. 



54 Of Reasoning. [Chap. II. 

9. All the parts of each are homogeneous, or exactly 
alike in kind. 

10. Every part of the one coexists with every part of 
the other. Every part of time exists everywhere, and. 
every part of space exists always. 

11. Their natures are essentially different; and one 
cannot possibly pass into the other. Time possesses no 
extension, and the parts of space never come into exist- 
ence, nor cease to exist. 

12. Every part of duration is preceded and followed 
by other parts of it ; and therefore it is eternal, or with- 
out beginning or end. 

13. Every part of extension is surrounded by other 
parts of it ; and, therefore, it is infinite, or without any 
bounds. (6) 

14. Duration consists of parts which come into exist- 
ence successively, and then cease to be forever ; and 
hence no two of them can coexist, nor can any of them 
which has ceased to exist, return, or exist again. 

15. The parts of extension all lie without each other; 
and, therefore, no two of them can coincide. 

16. Extension has position, but not form; and dura- 
tion has neither position nor form. 

17. Extension possesses mathematical solidity, or 
length, breadth and thickness ; but it does not possess 
resistive solidity, oi-, in other words, it can offer no re- 
sistance to the motions of bodies in any direction ; dura- 
tion possesses no solidity of any kind. 

C. Principles relating to Abstract Quantity. 

1. Abstract numbers are illimitable in amount, and 
homogeneous in kind. 

2. Abstract magnitudes are endlessly diversified in 
form and size ; and they consist of at least four essen- 
tially different kinds — solids, surfaces, lines, and angles. 

3. A solid has three dimensions — length, breadth, and 
thickness. 

4. A surface has only two dimensions — length and 
breadth ; and it may be considered the boundary of a 
solid. 

5. A line has only one dimension — length ; and it may 
be considered the boundary of a surface. 

6. A point has no magnitude, but only position; and 
it may be considered the extremity or end of a line. 



Sec. 2.] Special Pbinciples op Reasoning. 55 

7. A plane angle, or one formed by two straight lines 
meeting in a point, indicates only the difference of direc- 
tion of its two bounding lines, which is the sole measure 
of its dimension. 

8. The dimensions of a plane angle may be determined 
by the number of aliquot parts of a circular circumfer- 
ence intervening between its two bounding lines, the 
center of the circle being at the angular point. 

9. A solid angle, or one formed by three or more plane 
surfaces which meet in a point, termed its apex, indicates 
only the differences of direction of its bounding planes, 
which are the sole measure of its dimension. Planes, 
or plane surfaces, are those which are quite straight, and 
free from any curve or bend, in every direction. 

10. The dimension of a solid angle maybe determined 
by the number of aliquot parts of a spherical surface in- 
cluded between its bounding planes, the center of the 
sphere being at its apex. 

11. Number and magnitude are essentially different; 
but the latter may be measured by the former. 

12. Abstract quantity has no substantial existence; 
and, therefore, its nature and primary attributes can be 
known only by Intuition. 

13. Magnitudes are extended, and have form, size, and 
position. Numbers possess none of these ; they are only 
so many, and can occupy no part of extension. 

14. The whole includes all its parts ; and the latter are 
included in the former. 

15. The whole is*greater than a part ; and a part is less 
than the whole. 

16. Magnitudes which can be. made to coincide, are 
equal. 

17. If one of two homogeneous quantities is neither 
greater nor less than the other, it is equal to it. 

18. Things equal to the same thing, or to equals, are 
equal. 

19. If equals be affected by equals, the results will be 
equal. This principle comprises many others less gener- 
al, of which the five following are the most important. 

20. If equals be added to equals, the sums will be equal. 

21. If equals be subtracted from equals, the remainders 
will be equal. ' 

22. If equals be multiplied by equals, the products will 
be equal. 



56 Of Rzasoxesg. [Chap. II. 

23. If equals be divided by equals, the quotients will 
be equal. 

24. Like po>wegr& or roots of equals are equal. 

25. If imequals be affected by equals, the results will 
be unequal. This principle comprises the five following 
ones. 

26. If equcds be added to unequcds, the sums will be 
unequal; and that which includes the greater element 
will be the greater sum. 

27. If equals be subtracted from unequcds, the remain- 
ders will be unequal ; and the greater quantity will leave 
the greater remainder. 

23. If unequals be multiplied by equcds, the products 
will be unequal ; and the greater multiplicand will give 
the greater product. 

29. If unequals be divided by equals, the quotients are 
unequal ; and the greater dividend gives the greater quo- 
tient. 

30. Like roots or powers of unequals are unequal ; and 
the greater quantity gives the greater root or power. 

31. If the same operations be performed on several 
quantities, the results will bear to each other the same 
relations as the original quantities. This principle com- 
prises the 19th and 25th, but it is less explicit. 

32. If equcds be affected by unequals, the results will be 
unequal. This principle is the converse of the 25th, and 
comprises the five following subordinates. 

33. If unequcds be added to equcds, the sums will be un- 
equal ; and the greater is that which "includes the great- 
er element. 

34. If unequcds be subtracted from equcds, the remain- 
ders wiU be unequal ; and the greater remainder is that 
which is left by subtracting the smaller quantity. 

< 35. If equals be multiplied by unequcds, the products 
will be unequal ; and the greater multiplier gives the 
greater product. 

36. If equcds be divided by unequcds. the quotients will 
be unequal ; and the greater divisor will give the smaller 
quotient. 

3". Unlike roots or powers of equcds are unequal; the 
lower root of every number greater than unity is greater 
than the higher ; and the higher power of every such 
number is greater than the lower. 

38. A straight line is wholly in one direction. Hence, 



Sec. 2.] Special Pkinciples op Reasoning. 57 

it has two extremities or ends ; it can never return into 
itself, however far produced or extended ; nor can it in- 
close a space ; and only one straight line can he drawn 
from one point to another. 

39. A straight line may be indefinitely produced, or 
lengthened, from either extremity. 

40. Two straight lines cannot coincide in two points 
without forming one straight line. Hence two straight 
lines cannot inclose a space : otherwise one straight line 
might do so. 

41. A straight line is the shortest that can be drawn 
from one point to another. Hence any two sides of a 
triangle are together greater than the third. 

42. Straight lines which intersect or cut one another, 
lie in different directions, and diverge indefinitely, as they 
are produced. Hence straight lines which lie in the same 
direction will never meet, however far produced ; for oth- 
wise they would lie in different directions. 

43. The position of a straight line is wholly determ- 
ined by any two points in it, or, in other words, the po- 
sition of a straight line cannot be in the least changed, 
as long as any two points in it continue in the same po- 
sition. 

44. The direction of a straight line in a plane is whol- 
ly determined by the angle which it makes with another 
fixed straight line in that plane ; and, conversely, the 
size of the angle is wholly determined by the direction 
of the two straight lines. Hence straight lines which are 
in a plane, and make equal angles with another straight 
line in that plane, lie in the same direction, and, there- 
fore, can never meet, though produced ever so far ; and 
straight lines in a plane which never meet, make equal 
angles with another straight line which they intersect. 

45. Two straight lines which lie in different directions, 
or make unequal angles with a third straight line, and 
are in the same plane, will meet, if produced indefinitely. 

46. Two straight lines i?i the same plane which are in- 
clined to each other, or nearer at one point than at anoth- 
er, will meet, if indefinitely produced. Hence straight 
lines in a plane which never meet, however far produced, 
are parallel, or everywhere equidistant. 

47. Two straight lines in a plane which do not intersect 
each other, and are equidistant at any two points, lie in 
the same direction ; and, therefore, will never meet, how- 

C2 



58 Of Reasoning. [Chap. II. 

ever far produced, and, therefore, are everywhere equi- 
distant. 

I). Principles regarding the necessary properties qfSub- 

■;::: .1' :.' E-.\ :;••?. 

A Being is. ■whatever is. was, or "will be. Beings are 
unsubstantial and substantial. The former consist of 
those which are incapable of action or passion, including 
duration and extension, and the states, properties or re- 
lations of substantial beings : the latter comprise all oth- 
er beir _ b . S rib stances are either material or immaterial. 
The former are, those which directly aftect one or more 
of our senses, such as iron, water and air: the latter com- 
prise all those which do not so affect any of our senses, 
such as the minds or souls of men. Substances are also 
divided into inanimate and animate, or living. The for- 
mer are incapable of thought : the latter either think or 
have the power of doing so. 

The attributes or properties :: substances are of two 
kinds : — The n -; . ~hich every substance must pos- 

sess. and which are known only by means :: Liruition; — 
and the sonti . :. which a substance may or may no: [ : ; - 
sess, and which are learned by means of Comprehension. 

The following are the principal necessary properties 
:•: s".".':s-..v_::es. 

1. Every substance possesses resistive solidity, the na- 
ture of which is discerned intuitively. 

2. Every substance is extended in spaceman:. 

:' . . past, [ resent or future ; or, in other words, it must 
occupy some-portion of space, and exist during some por- 
tion of time. 

3. Every substance is numerically one, and can occupy 
only one part of space, at any instant of time : in other 
words, it cannot be two substances, nor be in two dis- 
tinct places at once. 

4. Every substance possesses form and magnitude, or 
it must have some shape and size ; and it can have only 
one form and size at any instant. 

f. The solid particles of substances are i :ssible 

and inextensible, or, in other words, their mass or quan- 
tity of solid substance can neither be increased nor di- 
minished, and much less annihilated. Bodies apparently 
sobd are frequently compressed; but this arises from, 
their being porous. 



Sec. 2.] Special Peinciples op Reasoning. 59 

6. Substances are impenetrable, or, in other words, two 
substances cannot occupy the same part of space at the 
same instant. 

7. Every substance must be either at rest or in motion, 
although it may be relatively at rest, and absolutely in 
motion, like a mountain, which partakes of the motions 
of the earth, though it is relatively at rest. 

8. Every substance is mobile, or susceptible of motion. 

9. All motion consists of a substance's passing from 
one part of space to another; 

10. Every motion is performed in time, or, in other 
words, no motion is instantaneous. 

11. Every motion of a substance is from that part of 
space where it is to that which is immediately contigu- 
ous. Consequently every substance which is found in a 
place different from one which it formerly occupied, 
must have passed continuously through every part of 
space along some course joining the two positions. 

12. A substance impelled by a force moves in the di- 
rection in which it is thus impelled, or, in other words, it 
moves in the direction in which it is made to move. A 
force is anything which changes, or tends to change, a 
substance's previous state of rest or motion. 

13. Force is requisite to change a substance's state of 
rest or motion. 

14. The velocity, or speed, of a substance is proportion- 
al to the force which generates it, if there is no counter 
action or interference of any other force. 

15. A substance affected by several forces which do 
not counteract each other, moves as if it were affected 
by one force equivalent to them all. 

16. Substantial beings alone are susceptible of change, 
this term being understood in its ordinary signification ; 
and every change consists of the motion of a substance 
from one part of space to another. 

17. Substantial beings alone are capable of thinking, 
or originating motion, although all beings of that class 
may not possess that power. 

18. Inanimate substances can have no desire or aver- 
sion. Hence they cannot be influenced by motives, or 
originate any change, and they can produce or undergo 
a change only where they are affected by some other 
agent, unless we assume that they were in motion from 
all eternity. 



60 Of Reasoning. [Chap. II. 

Of the necessary properties of living beings, the fol- 
lowing are the principal. 

1. Every living bei?ig is at least capable of thought., 
although he may possibly never have actually thought. 

2. Every thought is real, and the act of a living being. 

3. Every thought is precisely what it appears to be to 
the thinker. We must distinguish the thought from its 
object or cause, which may be different from what we 
believe it to be ; but this does not in the least affect the 
character of the thought. 

4. The presence or absence of thought is precisely as 
the thinker believes. We cannot believe that we do not 
think when we do, nor that we think when we do not. 

5. Belief without grounds satisfactory to the believer, 
is impossible, real and not professed belief being, of 
course, understood. The grounds of belief may, in real- 
ity, be conclusive ; yet if they do not appear to the indi- 
vidual of any weight, he will inevitably disbelieve. 

6. Belief against grounds satisfactory to the believer 
is impossible. The proofs may be really worthless ; yet 
if they appear satisfactory to the believer, he will neces- 
sarily believe. 

JEJ. Principles relating to determining Conditions and 
Agencies. 

1. Where the conditions which determine results are 
the same, the residts will be the same, however much 
other things may vary, the word " same" being taken to 
mean either absolute identity or perfect similarity. The 
determining conditions are, those things which determ- 
ine, limit or fix a thing to be what it is, and not different. 

2. Where the determining conditions are different, the 
results will be different, although other things should be 
the same. 

3. Any proposition established hi one case, independ- 
ently of particular circumstances, holds true of all cases 
which differ only in these circumstances. 

4. ~Wkat has once happened, must always happen, 
wherever all the circumstances which influence the result 
are the same. 

5. Every change is preceded or accompanied by mo- 
tion of one or more beings ; and change without motion 
is impossible. 

6. Every change must have its ultimate origin either 



Sec. 2.] Special Principles op Reasoning. 61 

in the volition of a thinking being, or in a substance 
which was previously in motion from all eternity. 

7. Every change is necessarily preceded by something 
which produces it, or on which it is dependent, called its 
Cause, and with reference to which it is termed an Effect ; 
or, in other words, everything which begins to be, is pre- 
ceded by something which makes it be, and failing which 
it would not be. The effect being dependent on the 
cause, distinguishes the latter from a uniform antecedent, 
and the foi"mer from a uniform consequent. (7) 

8. Nothing can produce only nothing, which may be 
otherwise expressed, something cannot spring from noth- 
ing. 

9. In order to produce a change, a cause must be ade- 
quate to produce it : but what are adequate causes must 
generally be learned from other intuitions, and from ex- 
perience. 

10. Where a cause known to operate, is found inade- 
quate to produce the whole of an effect, the residue is 
owing to some other cause. 

11. An agent cannot act where it is not / or, in other 
words, an agent can produce no effect where it is not, 
except by some medium. The Sun produces effects on 
the Earth by the mediums of light and heat, without 
which we could neither see it nor feel its warmth. (8) 

12. When tioo sets of agencies or forces operate, which 
tend to produce precisely similar effects, but directly 
counteract each other, the one set nullifies the other, and 
no such effect ensues, which may be more briefly express- 
ed thus : equal and contrary forces neutralize each other. 

13. The same cause, operating in the same circum- 
stances, always produces the same effect. 

14. An effect which depends solely on a particular 
cause, varies in proportion to the changes in the cause, 
and conversely ; or, in other words, effects are propor- 
tional to their causes, and the intensity of a cause is 
measured by the effect. Hence, where the result is ap- 
parently otherwise, one or more additional agencies must 
be concerned in its production ; and this is so frequently 
the case that an appeal to experience is generally requi- 
site, before we are warranted in assuming that no such 
second agency is concerned. 

15. Where several agencies or forces exactly co-operate 
or combine, to produce a particular effect, the result is 



62 Of Reaso:stn"G. [Chap. II. 

the same as would be produced by a single agency equal 
to the sum of those agencies. 

16. A body, or a connected system of bodies, is in equi- 
librium when the forces which tend to move it in a cer- 
tain direction are equal to those which tend to move it 
in the contrary direction. By a " body" is understood a 
material substance. 

17. Where a body is urged in contrary directions by 
unequal forces, it will move in the direction in which it 
is impeUed by the stronger force, as if it were affected by 
a single force equal to their difference. 

IS. When the cause ceases to act, its effect ceases to be 
produced. This principle must not be confounded with 
the very different proposition that an effect already pro- 
duced will cease to exist when the producing cause ceases 
to operate ; a proposition which is not even true. A 
change already produced may be permanent, or produce 
farther changes, although its cause may become inopera- 
tive, or even cease to exist. Thus, if a man ruins his 
health by dissipation, it is not immediately restored when 
he ceases to dissipate, and perhaps never ; yet it is self- 
evident that, when he ceases from his bad habits, he will 
suffer no further injury directly from that cause. 

1 9. The presence or absence of the cause proves the 
presence or absence of the effect, provided there is no 
counteracting or interfering agency. 

20. The presence or absence of the effect proves the 
presence or absence of the cause, if the former has not 
been removed by some extraneous agency. 

The following are the most important principles re- 
garding desires and volitions : 

1. A regard to good and evil is the only cause of the 
free or voluntary acts of living beings. 

2. Every volition, or act of will, has for its object the 
greatest apparent good y ox, in other words, the greatest 
apparent good is always willed. By the greatest appar- 
ent good is meant that which the individual believes to 
be such, although it is frequently by no means the great- 
est real good. 

3. That which will apparently secure more good, is 
willed before that which is believed to secure less; and 
where one of two evils is deemed inevitable, that which 
appears the less is willed. 

4. Every apparent good is an object of desire ; and ev- 
every apparent etu7is an object of aversion. 



Sec. 2.] Special Principles of Reasoning. 63 

5. Where there is no knowledge or belief regarding 
good or evil, there can be no volition or voluntary action. 

6. Where the apparent good and evil are precisely- 
equal, there can be no volition or voluntary action. 

*l. Where two objects appear, in every respect, equally 
good, there can be no choice. 

8. Every voluntary action conforms to the decision of 
the Judgement which pronounces it a means towards the 
greatest good. 

9. A change of the Judgement or of belief regarding 
good and evil, is followed by a corresponding change of 
volition. 

F. Principles of Inclusion and Exclusion. 

1. A thing cannot be, and yet at the same time and in 
the same sense, not be. 

2. An attribute cannot be truly affirmed and denied of 
a thing, at the same instant. 

3. No being can possess either contradictory or incom- 
patible attributes or properties. 

4. Of two contradictory propositions, one must be true 
and the other false. Hence, if one is true, the other is 
false, and conversely. 

5. Of two contrary propositions, both cannot be true, 
but both may he false. It is not generally necessary that 
a being should possess either of two contrary attributes, 
but it cannot possess both. Thus, the sky is neither 
white nor black ; but if it were the one, it could not be 
the other. 

6. A proposition cannot be both true and false, in the 
same sense. Hence, if one of several propositions must 
be true, and all but one are found to be false, this one is 
true. So, every proposition is false which necessarily im- 
plies something incompatible with truth ; else the prop- 
osition implied would be both true and false. 

7. If one thing includes a second, this second, a third, 
and so on, then the first includes the last. This principle 
applies both to physical objects and to inclusion by nec- 
essary inference. Thus, if London is in England, and 
England, in Europe, London is in Europe. So, if all 
kings are men, and all men are mortal, then all kings are 
mortal. 

8. If one thing is equivalent to a second, this second, 
to a third, and so on, any one of the series is equivalent 



64 Of R-easoxxs-g. [Chap. LT. 

to any other. As equals are included under equivalents, 
this principle includes the former. 

9. A being possessing* the characteristic or peculiar 
marks of a class, is one of that class; and a being which 
wants these marks, does not belong to the class. The 
" characteristic" or "peculiar marks" of a class are, those 
properties which belong to every individual of a class, 
and to no other being. 

10. Every being possesses the essential properties of 
its class. Thus, a triangle must have three angles, and 
an animal must be alive. The " essential properties" of 
a class of beings are those "which distinguish it from all 
others, and the want of -which excludes a being from the 
class. 

11. The universal includes the particular ; or, in other 
words, whatever belongs to a class individually, belongs 
to every one of that class ; and whatever is -wanting in a 
class individually, is -wanting in every one of that class. 
Thus, if John is one of a class of beings individually ra- 
tional, he is rational ; and if he is one of a class of ani- 
mals individually wanting fins, he is finless. This prin- 
ciple enables us to express a universal truth in an indef- 
inite variety of less comprehensive forms. 

12. Whatever belongs to every individual of a class, 
belongs to the class ; and whatever is wanting in every 
individual of a class, is wanting in the class. 

13. If some property of a thing is proved, all incom- 
patible properties are disproved. Thus, if it is proved 
that a certain man is virtuous, it is disproved that he is 
vicious ; or, if it is proved that he is a cheat, it is dis- 
proved that he is honest. 

14. An exclusive and uniform consequent, concomitant 
or antecedent of a phenomenon, proves its past, present 
or future existence. This principle applies only where 
the connection of the two things is already known, -which 
is generally ascertained either by their being necessarily 
connected as cause and effect, or by their being the ef- 
fects of a common cause. 

15. A common consequent, concomitant or antecedent 
of a phenomenon proves its provable past, present, or fu- 
ture existence : and the probability varies according to 
the extent of the connection, which is learned chiefly by 
previous experience of similar cases. 

16. Every intuition is self-evident, whether expressed 



Sjec. 3.] Pkocjsssks anj5 Ckiteeions. 65 

universally, generally, or particularly : and hence it may 
assume an indefinite number of forms, all of which are 
self-evident, if properly expressed. 

17. A thing either is or is not. This is the formula of 
alternation ; and it is extensively employed to determine 
ail the possible conditions of a problem. 

1 8. The existence of a property necessarily implies the 
existence of something of which it is the property ; and 
a property cannot inhere in anything with which it is in- 
compatible. This principle is extensively applied, in its 
special forms, in ascertaining the existence and qualities 
of objects. 

§ 3. Processes and Ceiterions op Reasoning. — Method of estab- 
lishing a Conclusion. — Primary Premises, Conclusion, and Chain 
of Reasoning. — Requisites to render a chain of reasoning valid. — 
Testing Syllogisms. — Parts of it often overlooked. — Ultimate foun- 
dations of all valid reasoning. — Two modes of testing a chain of 
reasoning. — Things to be examined, in all cases. — Effect of Am- 
biguity or Obscurity. — Two modes of proceeding. — Where both 
should be adopted. — Advantages of considering connectives gener- 
ally. — Allowable course where any of the conditions of valid rea- " 
soning are wanting. — Nature and various kinds of Arguments. — 
Collateral chains of Reasoning. — Nature and use of Combination. 
—Representation of a complex Argument. — Proving too much. — 
Why the faculty of reasoning cannot be successfully impugned. — 
Relation of Reasoning to Language. — Evils of not looking beyond 
words, in reasoning. — How Memory and Language aid reasoning. 
— Other aids. — Judgement, and Intellect. 

In establishing the proposition in question, it is gener- 
ally requisite to proceed by degress : the first proposi- 
tion, which we term the primary premise, is discerned to 
imply a second, this second, a third, and so on, to the last 
inference, or conclusion, the premise of one syllogism be- 
ing the inference of the preceding. The whole series is 
termed a chain of reasoning, the syllogisms being com- 
pared to links ; and it may consist of an indefinite num- 
ber of these. The conclusion is always connected with 
the primary premise by means of the seventh principle 
stated in the last subdivision of the preceding section, al- 
though it is so obvious that it is rarely expressed. 

The nature of a chain of reasoning may be exhibited 
to the eye by the following diagram : 



66 Of Reasoning. [Chap. II, 

^Primary premise. 
First connective < 

VFirst inference and second premise. 
Second connective < 

>Second inference and third premise. 
Third connective < 

>Third inference and fourth premise. 
Fourth connective < 

SLast inference, or conclusion. 

To render a chain of reasoning valid, it must possess 
the four following characteristics. 

1 . The primary premise must be all that it is rightly 
assumed to be. If it is assumed to be a discernment, it 
must not be an inference or a proposition founded on 
testimony ; and if it is assumed to be a supposition which 
is possibly true, it must not be an impossibility. So, if it 
is assumed to be proved by testimony, this must be con- 
clusive ; or if it is assumed to have been demonstrated 
by a process of reasoning, this must be valid. 

2. Every successive premise must be necessarily im- 
plied in that which immediately precedes it. 

3. The conclusion must be the real question, and not 
one merely like it. 

4. Every part must be understood or expressed clearly 
and accurately, so that there is no room for doubt as to 
what the exact things are. For, if this condition is not 
complied with, violations of the others cannot be de- 
tected. 

The strength of a chain is not greater than that of its 
weakest part ; and if one material link fails, the whole is 
worthless. 

In order to test the validity of a syllogism, we must 
discover the three parts. This is sometimes a difficult 
matter : for, not only are those parts frequently separ- 
ated from each other by wide intervals, both in spoken 
and in written. discourse, but w x e have often to gather the 
detached fragments of a proposition from various quar- 
ters, as it is nowhere distinctly stated. 

In many cases, the rapidity of thought leads us to 
overlook, in analysing, some of the syllogisms of the 
chain ; and hence, when we endeavor to trace the steps 
by which we arrived at the conclusion, flaws appear in 
the chain, while, in reality, it was continuous and conclu- 
sive. We must, therefore, beware of inferring that the 



Sec. 3.] Processes and Ceiterions. 67 

process by which we arrived at the conclusion was cer- 
tainly faulty, because we have failed to make out all the 
links of the chain. In many cases, a little careful exam- 
ination will make the defective links obvious. Yet we 
ought never to adopt conclusions as certainly true until 
we obtain the evidence of consciousness, at every step, 
although it is frequently difficult, especially for persons 
unaccustomed to analyse thought, to retrace all the men- 
tal processes. 

Reasoning often starts with propositions that are ac- 
knowledged to be true by the party to whom it is ad- 
dressed: but, to render a conclusion absolutely estab- 
lished, we must commence with truths of immediate con- 
sciousness, or, in cases of hypothetical reasoning, wi 4 ' 
the original suppositions. For discernments and suppo- 
sitions necessarily form the ultimate foundations of all 
reasoning. "We cannot reason from infinity; and we 
must begin with what is self-evident, or what, without 
being so, is known by direct consciousness, or with some- 
thing that we assume or suppose to be true, although it 
may be only a probability, or purely hypothetical. 

We may examine the validity of a chain of reasoning 
by tracing it fi'om the primary premise to the conclu- 
sion : or we may begin with the latter, and trace it back 
to the former. In both cases, we must always examine 
what the proposition under immediate consideration is, 
and whether it is necessarily connected with those adja- 
cent. If an obscurity or ambiguity occur in any part, 
the whole chain should be held invalid, until the diffi- 
culty has been cleared up : for, otherwise, we cannot as- 
certain whether the necessary connection exists, and soph- 
istry may occupy the place of sound reasoning. Owing 
to the defects of language and to loose or inaccurate 
thinking, it is sometimes difficult to discover the exact 
import of a material proposition ; but this must always 
be done, before we can ascertain whether the reasoning 
is valid. 

If we begin with the primary premise, we are first to 
consider whether it requires proof. If it does, the whole 
chain is baseless : if not, we then examine what the first 
inference is, and whether it is necessarily implied in the 
premise. If so, we then examine what the next infer- 
ence is, and so on, till we come to the final conclusion. 
If this be not the real question, the whole chain is worth- 
less, since it is beside the subject. 



68 Of Kbasoning. [Chap. II. 

If we begin with the conclusion, we first consider what 
the real question is, and then ascertain whether this is 
the very inference drawn from the premise immediately 
preceding. If so, we then find out this premise, and con- 
sider whether it necessarily implies the conclusion. If 
so, we search for the premise whence the former was in- 
ferred, and so on, till we come to the primary premise. 

In cases of importance, it is proper to try the validity 
of a chain of reasoning both ways. In determining 
whether a premise really implies the inference drawn 
from it, we need not consider the connective in a more 
general form than the particular connection demands: 
but it is desirable to understand its universal nature, as 
we can thus, in many instances, more clearly discera the 
connection, and apply the principle more readily and safe- 
ly in other cases. 

Wherever we find an absence of any of the four con- 
ditions of conclusive reasoning, we need not proceed far- 
ther: for one essential defect invalidates the whole. A 
chain of reasoning resembles one of iron, employed to 
move a weight, which must be sound in itself, attached 
to a moving power of sufficient force, and also fastened 
to the proper weight, and which fails of effecting the 
object if there be a defect in any of these respects. The 
case where the moving power is deficient, or the chain 
not sufficiently secured to it, corresponds to that of an 
unsound or inadmissible premise : that of a weak or 
broken chain corresponds to a flaw or obscurity in the 
reasoning ; and the case of the chain being fastened to 
the wrong weight answers to that where the conclusion 
proved is not the proposition in question. 

An argument is, what is employed to prove a conclu- 
sion. It may consist of a single syllogism : but it is more 
frequently made up of several collateral chains of reason- 
ing, or a combination of such chains, often blended with 
matters which are assumed as known or true — all con- 
verging towards the conclusion. Some of these chains 
may be either essential parts of the argument, or inde- 
pendent of the rest, and only employed to corroborate 
or strengthen the conclusion deduced from them. 

Several primary premises are often employed to prove 
a more general proposition, which embraces them all, 
and is tantamount to the whole of them taken together. 
When this identity has been ascertained, we infer the 



Sec. 3.] Processes and Criterions. 69 

truth of the general proposition upon the principle al- 
ready stated, that the character of a proposition is iden- 
tical with that of others tantamount to itself. Several 
of the new propositions, thus established, may be em- 
ployed, in the same way, as premises to prove a still 
more comprehensive conclusion, and so on, the whole 
process resembling the confluence of streams, where riv- 
ulets flow together to form brooks, and several of these 
unite to form rivers, while the independent parts may 
be compared to streamlets that flow directly into the sea. 

In such cases, we first observe the various things al- 
ready proved or known, which we desire to embrace in 
the more general proposition, then search for a suitable 
expression, which we compare with them, in order to 
ascertain whether it comprises them all and no more. 
When that has been done, we infer that the compre- 
hending proposition is true, and employ it accordingly. 

Such a process may be termed combination. Although 
it merely embraces in a more general proposition partic- 
ular or narrower ones previously known, established, or 
assumed, yet it is of much importance, as it greatly aids 
Memory and Reason in establishing comprehensive con- 
clusions. Without such aid, the Attention and the Mem- 
ory would be so confused that the bearings of the previ- 
ous cognitions could not be discovered, and we should, con- 
sequently be unable to connect them with the conclusion. 

Every distinct part of .an argument is to be tested in 
the manner already pointed out, as if it formed the whole. 
But we should carefully observe whether the things com- 
bined are tantamount to the comprehending proposition 
to which they are assumed to be equivalent : for, in many 
instances, they are so only with certain restrictions or 
modifications, which are apt to be overlooked, or they 
contain less than is assumed. 

The nature of a complex argument may be illustrated 
by the following figure. 

Intuition Perception 

.-Premise (combining both) ^-Emotional truth 

Connective-^ Connectives 

^Inference Testimony Sensation ^Inference 



Premise 
(combination) Corroborative Corroborative 

Connective J. inference testimony 



^0 Of Reasoning. [Chap. II. 

The fallaciousness of an argument sometimes appears 
from its proving something which we know to be un- 
true, equally with the conclusion which it is employed to 
establish. Arguments of this kind are said to "prove 
too much," and are evidently invalid: but we must be- 
ware of assuming that they are so, merely because this is 
alleged ; for opponents sometimes make such allegations 
when the argument is, in reality, irrefragable. An argu- 
ment which is conclusive in itself, cannot possibly prove 
too much : otherwise the same proposition would be both 
true and false. 

All attempts to impugn the faculty of reasoning are 
fallacious : for they necessarily assume its faithfulness, 
while they profess to prove the contrary. We cannot 
proceed a step to impeach it, without first assuming its 
entire reliability ; and if we can trust its conclusions in 
one case, we are evidently bound to receive them in all 
other cases equally unobjectionable. A difficulty some- 
times occurs from its leading to apparently contradictory 
conclusions : but, as it is self-evident that contradictions 
cannot both be true, there must be some fallacy in one 
or other of the processes, which a careful examination 
will always detect. Consequently the discrepancy is 
only apparent ; and such difficulties only prove that we 
are liable to reason erroneously or inconclusively, a truth 
of which we have frequent proof. Yet it is possible to 
test reasoning, so that we shall certainly know whether 
it contains any fallacy. 

Although language and other signs of thought are fre- 
quently of the utmoft use in reasoning, yet we cannot 
reason closely and conclusively, in all the most difficult 
subjects of investigation, without discarding all such 
signs, and directly considering the things signified : oth- 
erwise we may possibly be reasoning merely about words, 
and continue ignorant of what they profess to denote, a 
thing which has very frequently occurred. Words are 
merely signs of thought : and unless we discern a neces- 
sary connection between the things signified, independ- 
ently of their signs, our conclusions may possibly hold 
true only of the latter. For words are frequently of 
dark or doubtful import, or wholly unintelligible to the 
party addressed ; and the difficulty can be removed only 
by determining the nature and necessary relations of the 
things signified, which cannot frequently be done with- 
out considering them, wholly apart from language. 



Sec. 1.] Apprehensions. 71 

Whence once we have clearly understood the exact 
nature and extent of the things denoted by language, it 
enables us to substitute signs or symbols for the things 
signified ; and thus we can arrive at conclusions other- 
wise unattainable, while, in other cases, the process of 
reasoning is greatly facilitated and abridged. 

Memory aids reasoning by enabling us to substitute 
similitudes for their prototypes, and thus to reason about 
things absent as if they were present, while language en- 
ables us to discard even similitudes, for the time being, 
and substitute in their place mere visible or audible signs 
or symbols of them. Such aids are generally requisite, 
in order either to establish or retain general or recondite 
truths. 

Comprehensions form the starting point of all knowl- 
edge, since they are requisite to rouse our intellects into 
action, and, at the same time, they furnish the funda- 
mental elements of all contingent knowledge. Abstrac- 
tion is also requisite in all reasoning regarding matters 
which present any difficulty. Hence the faculties of 
Apprehension, Memory, Abstraction and Reasoning are 
designated by the common term Judgement, which dif- 
fers from Intellect in excluding Conception. This faculty 
is comparatively feeble in the greater number of man- 
kind, and much more rarely used in discovering truth. 

The conclusions drawn from premises whose character 
has been investigated by the aid of the Judgement, are 
termed judgements. (9) 



CHAPTER III. 

OE THE PRIMARY MEANS OE ACQUIRING CONTINGENT 
KNOWLEDGE. 

§ I. Keality of Apprehensions, and Means of avoiding the pri- 
mary Errors which they occasion. — Origin of Errors attributed 
to the Senses. — How Apprehensions may be distinguished from 
Ideas. — Specters. — Apprehensions necessarily real. — Distinguisha- 
ble from their causes. — Inferences from them often erroneous. — 
How these may be tested, and errors avoided. 

Although the senses are frequently occasions of error, 
yet, strictly speaking, they never deceive ; and all the er- 
rors attributed to them arise either from confounding 



!72 Acquiring Contingent Knoaveedge. [Chap. III. 

apprehensions and ideas, or from drawing unwarrantable 
inferences from the former. 

To avoid errors of the first class, it is only requisite to 
attend to the peculiarities of ideas and apprehensions. 
The former are readily distinguished from the latter, 
wherever the apprehending organs are sound, not only 
by their shadowy and fleeting nature, but also by then- 
being generally under the control of the Will. If we 
think of a well-known tree, which is at the moment in- 
visible, the likeness of it which we discern is much faint- 
er than if we actually viewed it; and it vanishes alto- 
gether, in a very short time, unless a conscious effort 
of the Will detains it; and if we so will, it vanishes at 
any instant, whereas the apprehension is not only much 
stronger and more distinct, but it cannot be willed away, 
while we behold the tree. 

In some cases of very forcible apprehensions, or a dis- 
eased condition of the organs of sense, ideas acquire un- 
usual vividness and permanence, and are, therefore, pe- 
culiarly liable to be mistaken for their prototypes. This 
remark applies particularly to objects of sight and hear- 
ing, which are, in such cases, termed specters, or spectral 
illusiom. Yet, even here, the shadowy character of ideas 
is still discernible. Error arises chiefly from the atten- 
tion being so concentrated on the idea that the difference 
between it and the apprehension is overlooked, although 
some palpable difference always exists. Thus, even after 
looking at the Sun, when the specter is still seen, in spite 
of all efforts to will it away, the difference is so palpa- 
ble that no person need confound it with seeing the real 
disc of the Sun. (10) 

The presence of something closely resembling an ob- 
ject, is apt to produce the same illusion as disease, espe- 
cially where the organs are placed in unfavorable circum- 
stances, and the mind is affected with any strong emotion. 
A dark log seen in a wood at night, may lead a timid 
person to think that it is a robber, lying in wait for his 
victim, the excitement probably causing an unusually viv- 
id idea of some grim countenance to arise, and complete 
what the real object lacks. But, in all such cases, we 
have only to view the object calmly and attentively, in 
order to avoid erroneous conclusions. Wherever disease 
affects the apprehensions, there are discoverable indica- 
tions of its presence, to put us on our guard ; and we 



Sec. 1.] Apprehensions. 73 

have only to attend carefully to all that is actually dis- 
cerned, in order to avoid error. 

In some cases, disease causes objects to affect us differ- 
ently from what they do in health. But such changes do 
not in the least affect the reality of the apprehensions : 
they only warn us to be cautious in assuming that ob- 
jects are what they appear to a diseased organ. 

To mistake an apprehension for an idea, is a very rare 
occurrence, because the characteristics of the former are 
so palpable that a very slight degree of attention suffices 
to identify it. Hence such a mistake hardly ever occurs, 
except where the thing apprehended is so strange or un- 
expected as to astound us, and consequently withdraw 
the attention from the actual apprehension. 

When we have observed the characteristic marks of 
an apprehension, any mistake regarding its reality is im- 
possible. When we feel heat or cold, for example, or per- 
ceive certain colors, the only question is, whether they are 
not mere ideas, as the reality of the comprehension ad- 
mits of no doubt. What causes it, is quite another mat- 
ter, which should not be confounded with its reality. In 
order to test this, we have only to ascertain whether it 
possesses those peculiarities which distinguish it from 
ideas. If it does, its reality is certain. If a man should 
seriously offer to prove to us that we felt cold, saw 
certain colors, or heard certain sounds, when we ac- 
tually did so, we should justly consider him deranged ; 
and such an offer would be still more ridiculous if we did 
not so' apprehend. It is self-evident that apprehensions 
cannot exist without being real, that they exist only be- 
cause they are apprehended, that they are precisely as 
they are apprehended, and that, unless they were appre- 
hended, they could not possibly exist. Their being ap- 
prehended, therefore, necessarily implies their reality, just 
as they are apprehended. 

Apprehensions should not be confounded with their 
causes, which are widely different things, but with which 
they are very liable to be confounded. Apprehensions 
are purely mental phenomena, while their causes are ex- 
ternal things totally different from the mind, and some- 
times at a great distance. Two persons may be very 
differently affected by the same objects; yet this does 
not render the apprehension of each a whit the less real. 
When we see and smell a rose, the colors we perceive 

D 



T4 Acquiring Casnx^exstx Ksowxkdge. [Chap. TTT. 

exist only because we perceive them, just as much as the 
odor we feel exists because we smeli it. The flower has 
nothing either in it or on it like the colors we see, any- 
more than it contains something like the odor which we 
feel, but only something widely different, which causes 
these apprehensions. 

In regard to the inferences deducible from apprehen- 
sions, we are liable to err, as in the ease of other infer- 
ences : and this is the real source of most of the errors 
commonly attributed to the senses. When a person 
touches a bullet, with the points of his fingers crossed. 
he thinks there are two ; yet he does not actually per- 
ceive two. His apprehensions, however, partly resemble 
what he generally perceives when there are two ; and 
hence he hastily draws an erroneous inference. So, when 
we first see the Sun in the east, and gradually more to 
the west, we are apt to assume erroneously that we see 
it moving westward, whereas a little consideration will 
show that we see no such thing. All that we observe 
is, a change in the relative position of the sun and the 
direction of sight, while we hold the same apparent posi- 
tion. Now there is such a change : but whether it is 
owing to a motion of the latter or of the former, or of 
both, the senses say not. Nor do we see the road run- 
ning away, when we look out behind a vehicle in which 
we are traveling. We can see tilings only as they ap- 
parently are at the present moment ; and, therefore, we 
cannot possibly see a body moving. TTe think we do 
so, only because we confound our inferences with our 
perceptions. 

In all such cases as the preceding, the error has gener- 
ally been attributed to the senses, whereas they are er- 
rors of reasoning, and the senses indicate nothing but 
what is strictly true. To guard against such errors, 
therefore, all we require to do, is, to test the validity of 
the reasoning, as in other cases. When this has been 
done with the requisite degree of care, the certainty of 
the inference is established", beyond the possibility of a 
rational doubt. 

The validity of inferences from apprehensions can be 
tested, not only by a strict examination of the reasoning 
processes, but also by comparing our conclusions with 
those of other persons, or those of one sense with the 
evidence of another. Thus, if I see the likeness of a de- 



Sec. 2.] Primary Mental Processes. 75 

ceased person, I may feel with my hand, or a cane, wheth- 
er there is really any such being where he appears ; or I 
may inquire of others whether they see anything there ; 
and if I suspect that I hear a sound, without any impres- 
sion being made on the ear, I may look whether there is 
any sounding body within hearing, or ask others wheth- 
er they heard such a sound. We can also, in many in- 
stances, indirectly determine the truth, without any such 
appeals as the preceding. Thus, if I suspect that I see 
single objects double, I have only to look at my right 
hand, or some other object which I know to be single, 
and observe whether I see it double or single. 

§ 2. Primary Mental Processes by which Contingent Knowl- 
edge may be acquired. — Our own Existence implied in our Ap- 
prehensions. — These often independent of our Volitions. — Neces- 
sary inference. — Changes caused by our Volitions. — How we distin- 
guish Ourselves from other beings — learn the condition of our 
organs, through one sense — and move them at pleasure. — How we 
know the existence of other Substantial Beings. — Why mankind 
attribute the phenomena of Apprehension to their true causes, not- 
withstanding certain errors. — What these are. — Extrinsic and In- 
trinsic Properties. — Principal kinds of each, and how learned. — 
Particular means of learning Intrinsic Properties, from simple Ob- 
servation. — Causes of the Contingent Properties of Inanimate Sub- 
stances, and of Living Beings. — Connection of Apparent and Real 
Similarity. — Means of enlarging our personal Experience. — Acqui- 
sition of Language. 

My apprehensions, of which I am immediately con- 
scious, necessarily imply the existence of the substantial, 
living and thinking self; for I know intuitively that 
thought cannot exist in a nonentity, and that a being 
which thinks, must be substantial, living and thinking. 
When I view the sky or the fields, for example, I am im- 
mediately conscious of certain apprehensions which, I 
know intuitively, cannot be discerned by a nonentity, 
and must exist in a substantial being. This being must 
be capable of discerning the phenomena, or, in other 
words, he must be a living being ; else he could not dis- 
cern them. A dead rock or piece of wood cannot dis- 
cern anything, and much less can a nonentity, or mere 
vacuity. 

Some apprehensions are pleasant, and others painful. 
The former excite a desire that they should continue; 
and the latter excite aversion, or a desire that they should 
cease. Yet the actual result is often otherwise: the 



76 Acquieing Contingent Knowledge. [Chap. III. 

former cease, and the latter continue, in spite of my voli- 
tions to the contrary. If a person passes me with a bas- 
ket of fragrant flowers, the agreeable odor ceases when 
they are removed, however much I may will that it should 
continue ; and when a wasp stings my hand, the pain 
does not cease for some time, although I strongly will 
that it should. In many cases, changes occur while I 
have no desire or volition either way, as when I view a 
flowing stream, while I am quite indifferent whether it 
flow or not. Thus I learn that many of the changes 
which occur around me, are wholly independent of my 
wishes or volitions. 

Every change which I experience, must originate ei- 
ther from my own volitions, or from spontaneoxis mo- 
tions of my parts, or from one or more other beings ; 
and, as no being destitute of thought can originate mo- 
tion, my parts will not move spontaneously, unless they 
are the seat of distinct thoughts. In that case they would 
cease to be a part of myself, since a being possessing dis- 
tinct thoughts and power of motion, must evidently be a 
distinct being, and form n.o part of myself. All those 
changes, therefore, which I experience, independently of 
my volitions, are produced by one or more beings dis- 
tinct from myself. 

On the other hand, many changes are produced by my 
own volitions, including all my words and voluntary ac- 
tions. This appears conclusively from their uniformly 
following and conforming to all my volitions. For the 
phenomena exhibit so much tmiformity and regularity, in 
an endless variety of circumstances, that casual or chance 
agencies are wholly excluded, and no other being would 
so obsequiously anticipate all my wishes, and expend 
such an immense amount of skill and labor in deluding 
me, to no purpose, as he could have no possible motive 
for the deception. Moreover, the supposed being would 
possess contradictory attributes. He would be benevo- 
lent, since he often operated to procure me enjoyment — 
and he would be malevolent, since he often deluded me, 
and led me into severe and lasting pain, by gratifying my 
wishes. The being could not design to improve me by 
discipline, as I should be only a passive recipient of Avhat- 
ever he chose to bestow or inflict. 

Those changes cannot be caused, without any external 
reality, by different beings, some benevolent and some 



Sec. 2.] Primary Mental Processes. 11 

malicious : for either the stronger would exclude the 
weaker from all control, or, if they were equally strong, 
the one under whose power I fell, would retain his su- 
premacy. An indifferent being would evidently not in- 
terfere with me at all. (11) 

I learn the limits of my own person by observing that 
its parts are all firmly connected, and that they uniform- 
ly and immediately obey my volitions, without any ap- 
prehensible command or request, which no other object 
does. If I will to move my foot, under the belief that it 
exists, and is connected with me, I notice a change in the 
position of the colors, and feel some new sensations, as if 
I had actually moved it : but if I will similarly regarding 
any distinct object around me, there is no such change. 

So, if I will to move from the chair on which I sit to 
another, my limbs all move in harmony to my new posi- 
tion, while my former seat remains precisely as it was. 
Those objects are evidently parts of myself which are in- 
separably connected with me, and immediately obey my 
volitions ; and all other objects are not parts of myself, 
as they are unconnected with me, and do not move uni- 
formly and directly in accordance with my volitions, save 
when they ai'e attached to me by artificial means, or in 
immediate connection with some of my parts. 

I learn the position and other peculiarities of my or- 
gans, at any instant, through a particular sense, by first 
noting the perceptions and sensations which I experience 
when some other sense informs me of those peculiarities. 
Thus, I know the position of my right hand, at any in- 
stant, independently of sight or touch, by first marking 
the apprehensions discerned when I either see its position 
or feel it with my left hand ; and these apprehensions 
afterwards inform me of its condition, without any aid 
from other senses, as I justly infer that they are the same 
as when my apprehensions regarding it were precisely 
similar. 

When I know the condition of an organ of motion, a 
little experience enables me to move it at pleasure, as I 
know the very thing to be willed, in order to effect the 
required motion. 

The various changes I experience, which do not orig- 
inate with myself, must result either from one being or 
from several. The former supposition is known to be 
absurd, just as I know that my actions are caused by my 



7 5 Aoquibibg Coxtivge^tt Knowledge. [Chap. m. 

volitions. Hence those phenomena must he owing to 
several "beings ; and they may produce them either hy 
communicating various motions to me, by means of in- 
tervening substances, or by coming into direct contact 
with me. They can affect me only in one or other of 
these ways : for it is self-evident that they can cause no 
change in me without actual contact or a medium. I 
cannot evidently be immediately conscious of the pres- 
ence of any external object, unless it is directly in con- 
tact with mv living self. The immediate causes of those 
phenomena may be very different from the ultimate, or 
even the remoter, cause-. 

The various phenomena presented by the substances 
around me, imply that some of them possess thought, 
like myself, and others do not. For the former exhibit 
changes similar to those which precede and follow my 
own volitions, while the latter are either uniformly inert, 
and never act or move save when they are affect ed by 
some other substance, or they do so only in one particu- 
lar way, thus indicating that they are always passive. 
Th 3 supposition of the formers motions being caused by 
substances distinct from themselves, involves the absurd- 
ity already Luted out; and it implies the further ab- 
surdity that these beings employ immense pains and 
skill to delude me into the erroneous belief that there are 
other beings like myself, without any motive for their 
doing so. 

The only admissible inference, therefore, is, that I am 
surrounded by a great variety of real beings, some ani- 
mate and some not, the former of which feeL^ will and act 
as I do myself. Each class presents numerous kinds, 
which differ widely ; yet the essential distinction between 
the two is generally well marked throughout. There is 
one species of the former to which I evidently belong, as 
it is precisely like myself, while all the rest differ, some 
more and some le??. 

On applying the tests furnished by my various senses, 
I am only confirmed in those conclusions. If a friend is 
speaking to me, and walking near me, with a fragrant 
flower in his hand, I hear his voice and the sound of his 
footsteps, see his person and movements, and smell the 
odor of the flower, while he answers my questions or re- 
marks ; and if I lay my hand on his head, I feel it, as soon 
as I see the colors come in contact. At the same time 



Sec. 2.J Primary Mental Processes. 19 

the variations in the tones of his voice, his footsteps and 
motions, and the odor of the flower, correspond to those 
in his appearance, as if he were at different distances and 
in different positions. Sometimes the apprehensions are 
multiplied by the presence of many persons at the same 
time. 

These phenomena admit of no rational explanation ex- 
cept that they are caused by those things to which they 
are usually attributed: for the few other possible ex- 
planations involve gross absurdities. The phenomena 
exhibit a degree of regularity and uniformity which 
wholly excludes the supposition of their being casual or 
accidental, and that of another being designedly produc- 
ing them, labors under the difficulties already pointed 
out. Hence the only obvious supposition regarding the 
causes of apprehensions, is the true one. It not only ac- 
counts for them, with perfect precision, but every other 
supposition involves impossibilities. 

Mankind generally attribute the phenomena of appre- 
hension to their true causes, since these alone are obvi- 
ous ; but this is done, from early infancy, with such ease 
and rapidity that they overlook the process of inference, 
and take that to be an immediate discernment which is, 
in reality, an inference. This error causes difficulties 
when the subject is attempted to be investigated, be- 
cause those inferences are sometimes false, which the real 
phenomena of consciousness never are. Men also fall 
into the further error of overlooking the other possible 
explanations that may be given of the phenomena ; but 
this is of no consequence, since a careful analysis shows 
that these all involve absurdities. 

The contingent properties of substances, or those 
which are not self-evident, are of two kinds, extrinsic 
and intrinsic. The former consist of those which are 
known only by their causing in us certain apprehensions 
essentially different from anything inherent in the sub- 
stances, and apparently dependent solely on the form 
and arrangement of their molecules or atoms. The prin- 
cipal of these are, color, and those which produce the 
apprehensions of smell, taste and sound. These are made 
known to us directly, through the proper organs. The 
color of an object is learned by the eye — the smell, by 
the nose — the taste, by the mouth — and the sounds which 
they give forth, by the ear. 



80 Acquiring Co^tixgeyt Knowledge. [Chap. HX 

The intrinsic properties of substances consist of those 
which are inherent in them, and are not dependent mere- 
ly on their molecular structure and discovered solely by 
certain apprehensions produced in us in consequence of 
that structure. The principal of these are, particular 
form or shape, size, position, weight or gravity, inertia, 
mechanical texture, and the various qualities dependent 
on it, temperature, electric and chemical properties, life, 
and the various properties connected vrith it. 

We must distinguish the particular and actual quali- 
ties of a substance from the general properties of the 
same kind known by Intuition. "We know intuitively 
that every substance must have some form, size and posi- 
tion : but the actual form, size and position of a substance 
are contingencies which we must learn from experience, 
and which cannot be ascertained by Intuition. This class 
of properties is mostly inferred from phenomena, by va- 
rious processes, of which the following are the principal, 
belonging to the subject of this section. 

The eye perceives nothing but various expanded col- 
ors, which frequently change their apparent forms and 
positions ; and we learn the actual forms, distances and 
positions of the colored substances by drawing inferences 
regarding the causes of the apprehensions which they 
produce. 

If we feel with our fingers any object, such as a book, 
table or chair, and view it in different positions, we find 
that the outline of the colors presented to the eye corre- 
sponds exactly to the outline of the real form, as determ- 
ined by the touch. The time which the fingers take to 
move over its different parts corresponds to their appar- 
ent size, as exhibited to the eye. The apparent form is 
such as would arise from the rays of light passing in 
straight lines from every part of the object to the eye; 
and as this, in all ordinary circumstances, happens uni- 
formly, we learn that these rays move in straight lines. 

TVe also notice that the shades of color vary accord- 
ing to the particular form of that part of the object which 
is in sight. TVe readily distinguish a ball from a fiat disc 
by observing its darker hue towards the edges, while the 
latter exhibits no such difference ; and a little experience 
renders us familiar with the peculiarities and causes of 
the variations in the shades of color. Thus we learn to 
determine form, with the utmost rapidity, from the visi- 



Sec. 2.] Primary Mental Processes. 81 

ble outline and shading alone, without any application 
of touch. 

Painted imitations may sometimes deceive us ; and the 
hues of distant objects are so indistinct that we are apt 
to draw erroneous inferences regarding their forms. But 
cases of this kind do not affect the accuracy of our con- 
clusions regarding ordinary objects, within moderate dis- 
tances ; and even there, we have generally some reliable 
means of ascertaining the true form, without the aid of 
touch. A painting may often be distinguished from a 
solid by its not possessing the vividness of nature, and 
its not changing as we vary the position of the eye. "We 
also frequently know that the circumstances are such as 
to exclude the supposition of any painting being visible. 
So the different appearances of the dark spots on the sm*- 
face of the Sun, as it revolves on its axis, show us, not- 
withstanding its great distance, that it is a solid body. 

We can form an estimate of the size of a body which 
is quite close to us, by comparing it with that of our hand 
or foot : and when it is within a moderate distance, we 
form a judgement from its apparent size, the degree of dis- 
tinctness in its color and outlines, the number and mag- 
nitude of intervening objects, and comparing it with a 
body near it whose dimensions are known. A little ex- 
perience shows us the modes in which the appearance 
of an object varies with its position. But such methods 
furnish only approximations in any case ; and where the 
body is very remote, as the Sun or Moon, they wholly 
fail. The exact dimensions of objects can generally be 
ascertained only by actual measurements and calcula- 
tions. 

The distance of an object cannot possibly be appre- 
hended directly, since space is invisible ; and it is esti- 
mated in the same way that we judge of its size. In- 
deed the two properties are so related that a knowledge 
of one assists us in determining the other. We either 
form an estimate of its distance from its appearance, and 
then judge of its size, on the assumption that it is at such 
a distance, or, if we know its actual size, we can form an 
estimate of its distance from its appearance. 

Another criterion, which may be frequently applied to 

ascertain the distance of an object, is, the nature of the 

sounds which proceed from it : for this varies with the 

distance, which can consequently be determined approx- 

D 2 



82 Acquteixg Co2errs"GEN~r Knowledge. [Chap. HE. 

irnately from noting the character of the sound, as it 
strikes the ear. The differences in the sounds are learn- 
ed by noting their character when the distance is known 
by some other means. 

The direction of a visible object may be ascertained by 
observing its bearing, compared with the line whence the 
direction is reckoned. Sometimes the direction of an in- 
visible object is determined by observing the quality of 
sounds proceeding from it, as these affect the ear differ- 
ently according to the directions in which the sonorous 
undulations are moving ; and we learn the various mod- 
ifications by observing the character of the sound where 
the direction is known by sight, touch, or any other 
means. The form of the ear is such that sonorous un- 
dulations affect it variously, according to the directions 
in which they move. 

The direction of one distant object from another may 
be roughly estimated by determining the distance of 
each, and then observing the angle which they form with 
each other, measured from the eye of the observer. 

In a void we cannot distinguish one direction from an- 
other ; and hence the direction of an object can be de- 
termined only by observing its position in relation to 
three or more fixed points. "While, therefore, this posi- 
tion continues apparently the same, a change of direction 
is imperceptible, as when we sit in the cabin of a vessel 
which changes its direction, we are not sensible of the 
change, because everything we see around us preserves 
the same relative position. "Where there is an evident 
change of position, it is frequently difficult to ascertain 
which object has moved. When I look over the side of 
a ship, and see the water apparently moving astern, I 
cannot directly say whether the vessel is moving against 
the flood, or whether she is at anchor, with the tide or 
current flowing past. I can ascertain the real fact only 
by looking at the shore or some fixed object. 

The same remark applies to two railway trains which 
cross each other : and the apparent motions of the heav- 
enly bodies furnish another instance, which differs from 
these, however, in there being no fixed object to remove 
the difficulty. We are apt to think that the bodies move, 
and that the Earth is at rest, because they are apparent- 
ly much smaller than the latter, and every object around 
us preserves the same relative position. Our persons 



Sec. 2.] Peimakt Mehtal Pkocesses. 83 

appear to stand in the same vertical direction through- 
out the day ; and if we turn towards the pole-star, our 
two hands seem to point always in the same directions. 

When we know the distance and direction of an ob- 
ject, we know its position in space, in relation to our- 
selves : but we cannot determine absolute position, be- 
cause we cannot distinguish one part of space from an- 
other, and all objects around us may possibly be in mo- 
tion, and yet constantly preserve the same relative posi- 
tion. 

The weight of a substance may frequently be known 
approximately by observing its momentum or moving 
force, to which it is always proportional, for a certain 
velocity ; and, in all cases, it may be estimated by ob- 
serving the effects which the substance has produced by 
its motions. 

The inertia of a substance is its tendency to continue 
in its present state of rest or motion, and its requiring 
the application of force to produce any change in that 
state. The general property is learned by simple ob- 
servation ; and accurate measurements show that it is 
exactly proportional to the weight of the body. Hence 
the amount of the former is always known from that of 
the latter. 

The mechanical texture of a substance is frequently 
learned from simple observation. Thus we see that ice 
is solid, water fluid, and steam gaseous, and that iron is 
tough and rigid, glass hard and brittle, and moist clay, 
soft and plastic. 

The temperature of several substances may frequently 
be loosely determined from our sensations, or observing 
their heating or cooling effects on other substances, and 
sometimes from their very appearance. Thus, we know 
that ice is, generally colder, and steam warmer than li- 
quid water. 

Some of the chemical and electric properties of sub- 
stances may be learned by observation ; but most of them 
are discovered only by means of experiments. 

The peculiar characteristics of living beings may be 
learned by observing their modes of acting. Life is dis- 
tinguished by the power of originating. or stopping mo- 
tion, independently of external application or mere iner- 
tia; and the differences between the various classes of 
animals are learned from the modes in which they act, 



Si ACQBTEOJG CoKITHGHST KNOWLEDGE. [CHAP. IH. 

or are affected by the various circumstances in which, 
thev are found. Thus, some exhibit cunning, and others, 
simplicity : some are gentle, and others, fierce ; some are 
strong, and others, weak, and so forth. 

We know the nature of our own comprehensions by 
direct consciousness : and we infer that other beings of 
our own species discern as we do. when they are placed 
in the same circumstances with us, and exhibit the same 
appearances which we present when so situated. We 
reason upon the principle that the results are the same, 
where the determining conditions are the same. 

The causes of the contingent properties of inanimate 
substances must be owing to the form and arrangement 
of their atoms, and their being variously affected by oth- 
er substances. But we can seldom trace a particular 
property to any of these causes. TTe cannot show why 
gold reflects only the yellow, and grass the green rays. 
or why nitric acid corrodes iron and silver, while it does 
not affect gold or platinum. 

In order to trace the causes of those properties, we 
should require to know the atomical constitution of mat- 
ter : and this we can never do : for however much mi- 
croscopes may magnify, one of greater power might 
show that to be porous which formerly appeared to be 
solid. For the same reason, we cannot trace any con- 
nection between the different properties of substances, 
although such a connection may possibly exist. We 
cannot determine the tenacity of a metal from its color, 
nor its fusibility from its specific gravity. 

With regard to the properties of living beings, we 
are, if possible, still more unable to trace them to their 
causes, farther than we can do by pure Intuition. The 
causes of the origin and ultimate conditions of life, seem 
to baffle all human efforts to trace them. "We readily 
learn that certain conditions are requisite to life, and that 
death ensues when they are violated : but why this is so, 
nobody can tell. A small quantity of an apparently 
harmless substance causes speedy death, while a much 
larger quantity of another substance, apparently much 
more injurious, fails to do so. All that we can here ef- 
fect, is. to establish the existence of certain intermediate 
conditions or causes ; and even this is done chiefly by 
indirect means. 

With regard to the question whether substances ap- 



Sec. 2.] Primary Mental Processes. 85 

parently quite similar are so in reality, "we justly argue 
that they must generally be so ; otherwise some of their 
discoverable attributes would differ. Diamond and 
quartz are frequently similar in touch and appearance ; 
but chemical processes soon show that they are totally 
different in composition : and, by passing polarized light 
through them, we may discover some differences in the 
texture even of two diamonds. Nor can we certainly 
say that there may not be other differences which we 
cannot detect ; yet there must be a general similarity in 
the structure of all diamonds ; else they could not pos- 
sess so many common properties as they do. The same 
remark applies to all similar cases : for where all the ef- 
fects are alike, the causes must be alike ; otherwise there 
would be effects without any adequate causes. 

Our personal comprehensions necessarily furnish all 
the primary elements of our contingent knowledge : but 
we avail ourselves of the observations, reasoning, and ex- 
perience of others, by means of signs of thought. These 
are chiefly spoken and written language, by means of 
which the knowledge of one person may be communi- 
cated to all his contemporaries, and transmitted to the 
most distant times. 

We first learn spoken or oral language by a close ob- 
servation of the usages of those around us. The child 
learns the names of the visible objects around him, by 
hearing them repeatedly applied, where he knows the 
object designated; and he learns the names of qualities, 
by hearing them expressed by certain terms, where the 
things meant are obvious. The significations of verbs 
are acquired by observing the words applied to denote 
what is present to the senses, or to give an order which 
is immediately executed : and the significations of the 
less abstract words belonging to the other parts of 
speech, are acquired in the same way. These attain- 
ments amply suffice for extending his knowledge of the 
subject, by means of information derived from others, 
or marking their usages either in spoken or in written 
discourse. 

A knowledge of the vernacular enables us to learn the 
experience of those around lis, and to avail ourselves of 
their comprehensions as if they were our o-wn, while a 
knowledge of writing places within our reach all the 
most important facts known to mankind. 



5 : A : juihds 3 C mphstgeht KsowxagDcas. [Chap. HI. 

§ 3. Primary Exthbkai. Peocessxs bttthich; CoynKGEvr Ksarwi*- 
zz :-z ::.._•-" z: ^:;z:z.zz. — -::z; ".-.- _ "-. -■: r\ :: ;; :: :- -'.'-- :z-v±- 
cient. — Standard :: Weights and Measures. — Method of repeating 
and taking a Mean. — Reqniate to render it satisfactory. — On what 
assumption based. — Its Advani-iz^s. — Method :: A"roximation. 
— Method of Extension. — Sometimes combined -with [Repetition. — 
I Ee ans of measnring Terr sm all spaces. — Things which cannot be 
accurately measured. — A:_; ::' Sight and Hearing. — Various 
means of testing resul:;. — Erz :-riizez:>. — Oftwe kizis. — General 
objects of logical Experizzez:?. — One often subservient to sereral 
objec:;. — Where Experiments are generally requisire. — Eelation 
: Experiments to Comprehensions. — Use of risible Symbols. — 
Czrves. — Application of Symbols. — Tangible Writing. 

The methods iiscossed in the preceding section do 
not, in many cases, famish a sufficiently precise and ex- 
tensive knowledge of the subject : and, therefore, we re- 
quire the aid of several external processes. In observing 
quantity, for example, we can generally form only a 
rough estimate if its amount from simple apprehension; 
and when we wish to ascertain the exact amour.":. ~; 
must have recourse to numeration, measurements, and 
calculations. 

If a man sell a flock of sheep, at so much a head, he 
can possibly tell, at a glance, that there are more than 
one and less :L.an two hundred: but neither he nor the 
buyer can tell the exact number, by this means. In order 
to do t his, the sheej must 1 e counted. This pre Jess must 
be adopted whenever we desire to ascertain the exact 
number of single things contained in an aggregate of in- 
dividual objects, exceeding a few : and, in effecting it, 
direct and continuous numbering may often be abridged 
by means of the processes of Arithmetic. Thus, the pop- 
ulation of a town is ascertained by first counting that of 
the various subdivisions, and then adding together these 
items, the sum of which is the total amount. So we may 
:ain, with sufficient accuracy, the number of pores 
in the whole surface of the body, by counting the num- 
ber within a square inch, in different parts, till we ascer- 
tain the average, and then multiplying this by the num- 
ber of square inches in the whole area of the skin. 

The : ~:~. es : f Subtraction and Division are equally serv- 

: _e. when we require to ascertain differences and quo- 
tients or aliquot parts : and, by combinations of the sim- 
ple processes, all ordinary numerical problems can be 
readily solved, from facts learned by direct numeration 
or counting. 



Sec. 3.] Peimaey Exteenal Peocesses. 87 

In order to measure quantity accurately, some uniform 
standard is requisite : and we are furnished with it by 
means of the unvarying time which the Earth takes to 
perform a revolution on its axis. This enables us to de- 
termine the mean length of a solar day, ivhich is the more 
immediate standard of time. We have no direct percep- 
tion of the flow of time; and hence we do not know what 
time is occupied by a revery or a dream. We can, in- 
deed, form some estimate of the lapse of time by noting 
the number of objects of which we have thought during 
the interval, or the amount of work done, or the distances 
traveled by us, or bodily sensations, which indicate a par- 
ticular period of the day or year, and so forth. But such 
methods do not possess the accuracy required for many 
purposes. In order to this, we employ time-keepers, 
which are regulated by the apparent diurnal motions of 
the fixed stars, corresponding to the real diurnal revolu- 
tion of the Earth. 

By taking a pendulum which swings so many times 
in a mean solar day, under specified circumstances of po- 
sition, heat and atmospheric pressure, we are supplied 
with a standard of length, which serves equally for meas- 
uring surfaces and solids. Then, by taking a certain solid 
measure of pure water, of a given temperature, and un- 
der a given atmospheric pressure, we have a standard of 
weights. 

The ordinary modes of measuring and weighing are 
sufficiently accurate for common purposes. But, in many 
scientific processes, the instruments require to be con- 
structed with the utmost accuracy ; and, after using 
them with all practicable exactness and care, some expe- 
dients are still employed to eliminate errors. 

Accuracy is frequently obtained by repeating a certain 
measurement, with all possible exactness, and then taking 
the mean of the whole. Thus the diameter of the Earth 
has been determined from various accurate and inde- 
pendent measurements, no two of which gave precisely 
the same results, although they differed by less than one 
tenth of a mile ; and, by taking the mean of all those 
measurements, a result is obtained more reliable than 
that deduced from any single measurement. So the par- 
allax of the Sun has been similarly determined, to a great 
degree of accuracy, from different observations of the 
transits of Venus over its disc. 



88 AcQtnEOTG CoxTTN-Gzirr Knowledge. [Chap. HI. 

To render this method quite satisfactory, one measure- 
ment must be as reliable as another ; for, if some were 
made carelessly or with inferior instruments, they should 
evidently be excluded from those employed in determin- 
ing the mean. The process is based on an assumption 
which experience shows to hold true, and which the cir- 
cumstances of such cases warrant us in assuming, name- 
ly, that, in a great variety of measurements, all performed 
with equal care, with equally good instruments, and with- 
out any peculiar difficulties one way more than another, 
errors in one direction are very nearly compensated by 
those in the contrary direction, some falling just as much 
short as others go beyond the truth. 

This method may obviate errors due to defects of in- 
struments, as well as those arising from inaccuracies of 
observation ; and it sometimes enables the observer to 
eliminate errors due to defects in his instrument even 
without any aid from a second. Thus, if we carefully 
measure the angular distance between two stars, on dif- 
ferent parts of a graduated circular arc, and take a mean, 
we obviate any small error arising from inaccuracy of 
graduation. So, if we weigh a body in the different 
scales of the same balance, we can determine its actual 
weight, although one arm of the balance should be long- 
er than the other. Again, if we first balance the thing to 
be weighed with sand, and then replace it with weights, 
we determine its exact weight, independently of all the 
defects of the balance, provided only that it is easily 
moved by a very small weight ; for, as the circumstances 
are the same in both cases, the sand must balance equal 
weights. 

Approximation is another method of aiding apprehen- 
sion. The quantity sought is first found approximately 
from observation ; then, by means of this result, we find 
another quantity, which differs less from perfect accuracy, 
and so on, to any required degree of exactness. Instan- 
ces of this method are furnished by the ordinary modes 
of finding the successive figures of dividends and roots. 

Another method of aiding apprehension is, to extend 
our observations, so as to include many similar cases, or 
such as are separated by wide intervals of time or space. 
Thus, if we wish to know whether granite is of igneous 
origin, we examine the whole series of similar rocks, 
and notice a gradual change, through the serpentine and 



Sec. 3.] Pkimary External Processes. 89 

trap, till we come to the modern lavas, which are direct- 
ly known to be of igneous origin, whence we conclude 
that granite had a similar origin. So, in determining the 
exact length of the year, if we have two observations 
made at an interval of a thousand years, the errors of ob- 
servation will be so distributed that the result will vary 
from the average length of the year, during the interval, 
only by the thousandth part of their sum, whereas, if the 
two observations were made at an interval of one year, 
the result would "vary from the truth by the whole 
amount of those errors. 

Sometimes the method of extension may be combined 
with that of repetition, so as to secure the advantages of 
both. Thus, in measuring angular spaces with the re- 
flecting circle, the angle is repeatedly measured in such 
a manner that the error arising from defects of gradua- 
tion is constant, while the final measurement is the result 
of all, and secured against errors of observation as in the 
method of simple repetition ; and as that of graduation 
is equally distributed through all the measurements, it 
may be made, by means of the extension, as small as 
the observer pleases. 

Very small spaces are generally measured by means 
of such contrivances as a vernier and a micrometer. But 
the same purpose is sometimes effected by particular art- 
ifices. Thus, the diameter of a very slender thread or 
wire may be determined by laying ply beside ply, till 
they exactly cover some small known space, as the six- 
teenth part of an inch ; and if we find it takes thirty of 
them to do so, we know that their diameter is the four 
hundred and eightieth part of an inch. 

Many things hardly admit of any greater accuracy of 
measurement than simple observation affords, such as the 
intensity of a color, roughness and smoothness. With 
respect to all feelings, whether sensations or emotions, 
they evidently admit of no measurement. But, in all 
such cases, Comprehension enables us to determine the 
greater from the less within narrow limits ; and this is 
all that we require, in such cases, for practical purposes. 
Thus, although we cannot ascertain that one green hue 
is twice or thrice as deep as another, yet we can distin- 
guish the various shades, with great accuracy. So, we 
know that our sensation of pain is much stronger in the 
case of a severe burn, than in that of a slight abrasion of 
the skin. 



QO Acquiring Contingent Knowledge. [Chap. III. 

Sight and hearing, the two most prolific sources of ap- 
prehensional knowledge, are directly assisted by instru- 
ments. The speaking trumpet, by concentrating the aerial 
undulations, and the hearing or ear trumpet, by collecting 
them, enables us to hear distinctly sounds otherwise in- 
audible : and the simple device of changing the direction 
of the rays of light, by means of some refracting or re- 
flecting medium, enables us, on the one hand, to discover 
around us innumerable wonders otherwise invisible, and, 
on the other, to explore the regions of immensity, and 
countless systems of worlds unseen by the naked eye. 
The microscope is employed, not only as a means of dis- 
covering things otherwise indiscoverable, but also to 
measure small spaces with accuracy ; and this application 
of it forms a marked period in the history of Astronomy. 

The accuracy of results may often be tested by com- 
paring them with those obtained by different processes 
for effecting the same end, or by observing whether they 
lead to known truth or falsehood. Thus, astronomical 
calculations of eclipses and other celestial phenomena, 
may be compared with subsequent observations, and 
arithmetical calculations are verified by reversing the 
operations, and observing whether we arrive at correct 
results. So the accuracy of a whole trigonometrical sur- 
vey may be verified by compai'ing the calculated with 
the measured length of the last line, which is, therefore, 
termed " the base of verification." 

Another process, which is not only a means of testing 
results, but frequently a most important means of acquir- 
ing a knowledge of primary facts, is, experiment, which 
consists in operating with things, or placing them in pe- 
culiar positions, that we may mark the result, and thus 
illustrate a proposition, solve a difficulty, or discover 
some unknown truth, or some new means of effecting a 
known end. Experiments are either didactic or logical. 
The former consist of those which are performed for the 
purpose of illustrating or demonstrating known truth to 
learners : the latter comprise such as are made for the 
purposes of discovery or invention ; and it is with these 
alone that we are concerned at present. 

The immediate objects of most logical experiments 
are, to determine the amount of a certain thing, or one 
or more of its intrinsic properties, or what causes pro- 
duce known effects, or what effects are produced by 



Sec. 3.] External Processes. 91 

known agencies. Many experiments subserve two or 
more objects. Thus, experiments on the composition of 
water determine the component elements, the quantity 
of each, and the circumstances under which they com- 
bine and separate. 

Experiments are generally requisite wherever proper- 
ties, agencies or operations are hidden beyond the reach 
of direct observation or measurement, and are discover- 
able only by testing or trying them, with the aid of all 
that we previously knew of the subject. 

The nature of the phenomena of Comprehension can 
be known only by direct observation. Thus, nothing but 
the actual apprehending can enable us to know the na- 
ture of our apprehensions when we smell a flower or 
hear a sound ; and the ultimate processes of apprehen- 
sion are an inscrutable mystery. But, in determining the 
causes of phenomena, experiments are frequently of much 
use. Thus, if I doubt whether the table before me act- 
ually exists, I may attempt to strike it, and observe 
whether I experience new apprehensions when the colors 
of my hand and the table come in apparent contact. So 
we may sometimes learn how certain things affect the 
mind, by exposing it to their influence ; and, by exclud- 
ing some particular agency, we can occasionally ascer- 
tain how much is due to its influence in other cases. 

In many investigations, such as the processes of Math- 
ematics and Physics, little pi-ogress can be made without 
the aid of visible symbols, owing to the great difficulty 
of otherwise remembering the various steps of a process. 
Thus, ordinary geometrical propositions or dynamical 
theorems cannot be satisfactorily investigated without 
the aid of figures or symbols denoting quantity. So the 
laws of many variable quantities can be neither discover- 
ed nor effectually remembered, without expressing the 
several values either in tables, or by curve lines, whose 
distances from a point or a straight line vary as the 
quantity. Such are, the variations of atmospheric tem- 
perature and pressure, of the magnetic needle, tide-wa- 
ters, the expectation of life at different ages, and the 
progress of population in a community. Thus, if we ex- 
press by a continuous curve the height of the thermom- 
eter, at every hour of the day, we can form a correct es- 
timate of its diurnal variations ; and a similar curve, rep- 
resenting its daily average height, furnishes the same ad- 



92 Acquiring Contingent Knowledge. [Chap. III. 

vantage in regard to its annual variations. So a knowl- 
edge and remembrance of the leading events of History, 
are much facilitated by synchronistic tables. 

In all cases of this kind, we can dismiss from our 
minds, for the time being, the things denoted by the sym- 
bols, and concentrate our attention on the latter, while 
Ave can return to the former whenever we require to do 
so. We remember the general import of the symbols, 
during the investigation, so as to use them aright ; and 
we can afterwards recollect the particular things which 
they denote. Thus, in an algebraic investigation, we can 
remember which letters denote the known and which the 
unknown quantities : and, after the investigation is con- 
cluded, we can easily return to the particular quantities 
which every symbol denotes. 

Such devices as the preceding are frequently employ- 
ed to determine many points which might seem to be 
matters of direct observation. Thus, Kepler discovered 
that the planets revolve in ellipses, with the Sun in one 
of the foci, by representing their distances from it, in va- 
rious parts of their orbits, on paper, drawing a curve line 
through all the points of observation, and then determin- 
ing the nature of the curve, and the exact position of the 
Sun within it. 

Curves are extensively enrployed in those sciences 
which treat of variable quantities. They first assist the 
observer, not only in discovering the laws of variation, 
but also in eliminating errors of observation : for, as ab- 
rupt transitions seldom occur, in such quantities, a mere 
inspection of the figure will often enable him to detect 
errors, by the want of symmetry and regularity in the 
curve. Thus, if one point of a planet's orbit be found a 
little without, and the part immediately adjacent a little 
within an ellipse, the apparent discrepancies might be 
safely assumed, to arise from errors of measurement, 
since no such deflections from its former course can be 
attributed to the motions of the planet ; and hence it 
might be concluded that the true path is an ellipse. Aft- 
er the laws have been discovered, those devices facilitate 
both the remembrance of them and an understanding of 
them by others. 

Some representations are as perceptible to the touch 
as to sight ; and these are ingeniously applied to com- 
municate knowledge to the blind. Thus, by means of 



Sec. 1.] Reliability of Memory, &c. 93 

raised, instead of colored, letters, these unfortunate per- 
sons are furnished with books which they can read by 
running their fingers over the letters, instead of seeing 
them ; and practice enables them to do this with sur- 
prising facility. 



CHAPTER IV. 

OF THE PRIMARY MEANS OF RETAINING KNOWLEDGE. 

§ 1. Reliability of Memory, and Means of avoiding the Pri- 
mary Errors which it tends to produce. — Use and phenome- 
na of Memory. — Their possible sources. — How the true one is es- 
tablished. — Indirect proofs of the reliability of Memory. — Common 
errors. — Nature and requisites of Recognition. — Cases in which 
these generally exist, and in which they fail. — Phantasms. — Why 
Imaginations are sometimes mistaken for Ideas. — How this error 
may be avoided. — Consequence of other Similitudes recurring like 
Ideas, and of. the reality of all Similitudes. 

Our immediate knowledge of all contingent truths is 
confined to the present moment. Thus, we can neither 
see nor hear past or future events, which are made known 
to us only indirectly, through their being connected Avith 
the present, by means of Memory, Reason, Abstraction 
and Conception ; and the aid of the first of these faculties 
is generally requisite, in all such cases, to enable us to 
pass beyond the present. 

When objects of thought formerly apprehended, are 
again presented to our observation, the ideas of them 
arise spontaneously before the mind, generally accompa- 
nied by those of other objects apprehended at the same 
time. These ideas sometimes completely correspond to 
the present reality, and sometimes there are slight differ- 
ences : but there is generally a close and marked resem- 
blance. In apprehending objects for the first time, no 
such ideas present themselves. Many such ideas, again, 
occur spontaneously, according to certain laws, whereas, 
in order to form conceptions of things never apprehend- 
ed, we find that a conscious, if not a laborious, effort is 
requisite. These facts admit of no other rational expla- 
nation except that we previously apprehended the pro- 
totypes of the spontaneous ideas, but not the other class 
of objects, and that we are still the same persons. 

The spontaneous ideas must evidently arise from some 



94 Meams of Retaestxg Kxotvi.ege. [Chap. IT. 

fortuitous peculiarity of the organization, or from some 
conscious being designedly producing them directly ei- 
ther in the same person who formerly apprehended the 
prototypes or in a different person, or from our having 
actually apprehended the prototypes of the various ideas, 
and our being so constituted that ideas of objects once 
apprehended recur spontaneously, in consequence of be- 
ing related to some other thought. This last supposi- 
tion accounts for all the phenomena ; and each of the 
other two involves an absurdity. 

The corresponding ideas are so numerous, and, in many 
cases, consist of so many different parts, that a fortuitous 
production is absurd, since it would be a change without 
any adequate cause. This becomes very evident from 
the fact that a long succession of ideas often arises be- 
fore the mind while we actttally apprehend their proto- 
types, and in exactly the same order. Thus, if we view 
a well-known landscape, the ideas of the various objects 
spontaneously arise, as the eye beholds the successive 
parts, until we see the whole at a glance, when the men- 
tal likeness becomes equally complete. The supposition 
is rendered yet more absurd by the fact that the appre- 
hending of an object often calls up, not only a single idea 
of it, but also the similitudes of all our previous discern- 
ments regarding it. Thus, the sight of a well-known 
scene recalls the many views we formerly had of it. all 
of which present themselves to the mind simultaneously, 
or in very rapid succession. 

The second supposition, also, involves absurdities. For 
the being which produced the ideas in us, would be be- 
nevolent, since he often caused us joy, and also malevo- 
lent, since he often caused pain. He must also be desir- 
ous that we should know, since he labored so rnuch to 
produce elements of knowledge; and, at the same time, 
he must be desirous to mislead us, since we actually in- 
fer, as the most obvious explanation, that we apprehend- 
ed originals of those ideas. These objections apply still 
more forcibly to the supposition that he produced, in the 
minds of one person, ideas coreesponding to the appre- 
hensions of another. 

That ideas correspond to their prototypes, is proved 
directly by experience; for we often find that the appre- 
hensions were actually such as the ideas indicate. Thus, 
I have the idea of a certain writing, which I made in a 



Sec. 1.] Reliability of Memory, &c. 95 

book yesterday ; I turn to the book, and there I find it, 
exactly as the idea indicates. Again, I have the idea of 
a book laid in a certain place ; I turn towards the place, 
and there I see it. So the ideas of numerous instances, 
in which Memory was found faithful, often arise before 
our minds, and confirm its faithfulness. 

As the true explanation of the phenomena of Memo- 
ry is the only obvious one, and we are habitually accus- 
tomed, from our earliest years, to draw the necessary in- 
ferences, with the proverbial rapidity of thought, we are 
apt to think that we are immediately conscious of the re- 
ality of things remembered : but it is self-evident that we 
cannot be conscious of a past, any more than of a future, 
contingency. Mankind act here precisely as in the case 
of apprehensions : they draw legitimate inferences, but 
mistake them for immediate discernments, and overlook 
other possible, though really absurd, suppositions or ex- 
planations. 

We recognize an object when we find, on comparison, 
that the idea of it exactly resembles it, or very nearly so. 
If the object is not subject to change, there must be com- 
plete resemblance : but if it be subject to gradual changes, 
like most organic beings, we consider whether the differ- 
ence between the idea and the apprehension is not such 
as time may have produced, since we apprehended the 
object. Thus, if we have not seen a boy for three years, 
we make allowances for his change of stature and gen- 
eral appearance. 

When the idea is not very clear or complete, we are 
apt to commit mistakes. Thus, we frequently take a per- 
son not well known or long absent, for one who closely 
resembles him. In order to recognize an object with 
certainty, it must possess some peculiarity which distin- 
guishes it from all similar objects ; and we guard against 
the error of mistaking one for another by noting careful- 
ly those peculiarities, so that they may be remembered, 
and afterwards observing whether the object in ques- 
tion possesses them. Thus, a person otherwise greatly 
changed in appearance, is often recognized by some scar 
or mark, which distinguishes him from all others. In 
living beings, distinctive peculiarities are generally found 
without difficulty, every one having something in form, 
color, voice, gait, or aspect, by which it can be readily 
identified. This'is also the case, to a great extent, even 



96 Means of Retailing Knowledge. [Chap. IV. 

in the vegetable creation, and in most inorganic natural 
objects. There are no two trees or valleys in the world 
which cannot be readily distinguished from each other. 
But works of art frequently resemble each other so close- 
ly that we cannot, with certainty, distinguish them. In 
such cases, however, mistakes are generally, though not 
always, of little consequence. 

Similitudes of conceptions recur like those of ideas ; 
and thus we know what were our former conceptions. 
But as conceptions are composed of similitudes or their 
modifications, their phantasms are nearly as vivid as the 
original elements ; and hence error is apt to arise from 
mistaking them for ideas. This is particularly apt to oc- 
cur where the phantasms have long been considered at- 
tentively, so that they acquire the vividness of ideas, for 
which consequently they are sometimes mistaken, as 
where a man gives a fictitious account of his own per- 
sonal adventures, with an evident belief in their reality. 

To avoid such errors, we have only to recall the ideas 
of the circumstances under which we first conceived the 
prototypes. Conceptions are always produced by con- 
scious efforts of the Will, which distinguish them from 
apprehensions or ideas. When our remembrance of the 
prototype is so faint that we do not certainly know 
whether it is the similitude of a conception or an appre- 
hension, we cannot determine simply by Remembrance 
whether we originally apprehended or merely conceived ; 
and Ave must have recoui'se to some external means, in 
order to determine the truth of the case. 

The similitudes of all other thoughts follow the same 
laws of recurrence as those of ideas ; and hence Remem- 
brance enables us to know all our foi*mer thoughts. 

We are as conscious of the reality of similitudes as we 
are of that of their originals ; and, therefore, we can rea- 
son from the latter with as much confidence as we do 
from the former, while error must arise solely from draw- 
ing fallacious inferences. 

§ 2. Primary Processes bt which Knowledge is retained. — 
Means of knowing past Contingencies. — How we know the Time 
and Place of apprehending. — Forgetting. — Different simnltaneoiis 
ideas of objects. — Eecollecting. — Various kinds of External Signs. 
— Principle of their operation. 

Past contingencies are known by means of thing; pres- 



Sec. 2.] Primary Processes. 97 

ent which are signs or indications of them, the things to 
be remembered being so connected with the signs that 
a knowledge of the latter leads to a knowledge of the 
former. These signs are either Internal or External. 

Internal signs consist chiefly of similitudes, the general 
nature and operation of which have already appeared. 

The particular time and place of apprehending are de- 
termined by means of the ideas of objects apprehended 
simultaneously : and if these do not appear, we know 
only that we apprehended the object, and cannot say 
when or where. The faculty of remembrance, being 
wholly dependent on similitudes, cannot act where the 
latter cease to arise, in which case we are said to forget 
the apprehension. 

Where things have been repeatedly apprehended, the 
several ideas of them which appear simultaneously, some- 
times differ. Thus, when we see a person whom we 
have seen in health and sickness, the ideas of his differ- 
ent aspects frequently appear together. But the ideas 
of the other objects apprehended on the different occa- 
sions recall the various circumstances, and thus rather 
strengthen remembrance and corroborate its testimony, 
than produce confusion or difficulty. 

Although ideas arise spontaneously, they are always 
suggested by some other object of thought, which is so 
related to them that thinking of the latter leads us to 
think of the former. This peculiarity enables us to re- 
call ideas indirectly when we have lost the power of do- 
ing so directly. Thus, we may have forgotten where we 
saw a certain person, so that we cannot directly deter- 
mine the place : but we may know it was on such a day, 
and, by recalling its transactions, the idea of the person 
may be brought up, with that of the place where we saw 
him. In such cases, we are said to recollect our appre- 
hensions. 

External signs consist chiefly of direct likenesses of 
the things to be remembered, symbolic representations, 
either of the things or of speech, and phonetic signs of 
words. 

Direct likenesses consist of sculptures and casts, which 
are formed precisely like their originals, and of drawings, 
paintings, engravings, or photographs of the things to 
be remembered, which only represent, on a smooth sur- 
face, their appearance in certain positions. 

E 



98 Generalization. [Chap. V. 

Symbolic representations of objects represent them by 
means of some analogy or relation which they bear to 
the thing represented, as where a science is symbolized 
by a female figure, or a curTe is employed to point out 
the different values of a variable quantity, or a great 
event or character is commemorated by a monument, or 
periodic acts and ceremonies. 

Symbolic representations of words represent them by 
their having some real or fancied analogy to the thing 
denoted, or their being arbitrarily chosen for that pur- 
pose, such as— c£, ?, !, 1, 2, 3, -j-, — , -/• 

^Phonetic signs consist of characters which represent, 
not the objects of thought, but the simplest elements of 
speech, as a, b, c, &c. As those elements are by no 
means numerous, a few characters suffice to represent 
the whole of spoken language. (12) 

All external signs operate on the principle that the 
perception of the sign reminds us of the thing -sip 
The two things are so connected that when we perceive 
the one, Memory calls up the other. 



CHAPTER Y. 

OF (VRVT-R A T.T7 A TTOV. 

§ 1. Nattee of Gekeealizaiio>~. — Definition of Generalization. — 
Conceptions always particular. — All science dependent on Gen- 
eralization. — Distinction between the formation of Conceptions and 
the use of General Terms. — What the latter denote. — How their 
meaning is learned. 

Generalization is, discovering, by means of particular 
cases, general truths, or propositions which hold true of a 
whole class, such as — i; the Hon is carnivorous" — ' ; the 
Roman emperors possessed absolute power" — " men are 
mortal," and — i; fish five in the water." 

Not only is every real object in nature individual, but 
our conceptions also are equally particular. Xot only is 
there no general tree, river, house, or bird, in the world, 
but we cannot even conceive such things : we cannot 
form a notion of a tree that has no form, size or color, 
nor of one that has several forms, sizes and colors. Such 
conceptions are evidently impossible : and when we con- 
ceive of a thing as having particular attributes, the con- 



Sec. 2.] Nature oe Generalization. 99 

ception is as particular as any apprehension. We can- 
not conceive either of a substance destitute of attributes, 
or of one that possesses incompatible attributes. 

Other things denoted by common names are no more 
general than substantial beings. Thus, there is no gen- 
eral red, blue, hardness, death, justice, fraud or geome- 
try ; and we cannot form a conception of any such thing. 
"We cannot form a conception of a red color unaccom- 
panied by any particular substance that is red, or of death 
apart from any particular scene of death, or of justice 
apart from any particular act of justice, and so forth. 
Hence it appears that, without the aid of Abstraction 
and Generalization, our knowledge of nature would be 
confined to individuals, and science could not exist. 

We must not confound the formation of conceptions 
with the use of general terms, or words that apply equal- 
ly to every one of a class of objects. Such terms are 
often used without our having any immediate compre- 
hension of what they denote : but this does not, in the 
least, prove that there are general conceptions. When 
the word " mountain," for example, is mentioned in dis- 
course, we may possibly think of some particular well- 
kuown mountain, or of several mountains in quick suc- 
cession, or think of no mountain at all. The last suppo- 
sition frequently holds true, where something besides the 
thing meant by the word is forced on our attention, as in 
the expression — " the word mountain is of the singular 
number." Here the attention is apt to be wholly occu- 
pied with the words ; and a similar remark applies to 
those cases where we do not require to refer to the 
meaning of certain signs, during an operation, after fix- 
ing them at the beginning of a process of reasoning, as 
generally happens in Algebra. 

A general term is simply a word which is equally ap- 
plicable to a certain attribute, action, or relation, wher- 
ever it exists, or to every individual of a class. The 
meaning of such words is learned either from observa- 
tion or definitions. After noticing a few cases or speci- 
mens, we learn the nature of the thing signified ; and 
formal definitions often answer the same purpose. 

§ 2. Principal Processes of Generalization. — (1) Abstracting 
regarding some common observed attribute. — Naming Classes. — 
Empiricisms and Inductions. — Requisites to the latter. — Compari- 
son. — (2) Generalization from identity of agencies or conditions. — 



100 Generalization. [Chap. V. 

Requisites, in such cases. — On what this process is based. — (3) Rea- 
soning from the attributes which an individual possesses in com- 
mon with a class. — (4) Proving that all individuals of a class have 
certain attributes in common. — Attributes embraced in Definitions. 
— Uniformity resulting from uniformity of the Determining Agen- 
cies. — Consequences of the Character of the Deity. — Exceptions. — 
Limits of physical Inductions. — Common Error. — How the Uni- 
formity and Stability of Nature is logically established. — Means of 
distinguishing Specific from Individual Peculiarities. — Attributes 
common to a Species. — Means of detecting Anomalies. — Princi- 
ples by which Inductions are established. — Why Intuitions do not 
require generalization. — What constitutes an Induction. 

The following enumeration includes the most common 
and important of the processes of generalization : 

• 1. We examine several objects, and compare them, ei- 
ther by direct simultaneous inspection or by the aid of 
Memory, and notice, by means of the faculty of Abstrac- 
tion, the attributes which they possess in common : and 
then we express these in a general proposition, by the 
process of combination. In surveying animals, for ex- 
ample, and abstracting as to their external forms, we ob- 
serve that some, though differing widely in other re- 
spects, all agree in having four feet, as oxen, sheep, dogs 
and cats ; some have four hands, as monkeys and bab- 
oons ; some have two feet and two feathered wings, as 
hens and hawks ; and man alone has two hands and two 
feet. 

We may now express the possession of the common at- 
tribute by a general proposition, including all the particu- 
lar ones, and give every one of those classes a name, equal- 
ly applicable to every individual belonging to it, and dis- 
tinguishing it from all others. Thus, we may call the 
first class quadruped or four-footed — the second, quadru- 
man ox four-handed — the third, feathered — and the last, 
biman or two-handed. Any other intelligible words 
would suffice for the purpose of generalization, such as 
simia, instead of quadruman, bird or avis, instead of 
feathered, and man or homo, instead of biman. There 
is a manifest advantage, however, in having a term which 
denotes the essential jjeculiarity of the class, although 
this cannot frequently be obtained without inventing a 
new word. 

In the same way we generalize regarding actions, 
modes of action and relations. We see, for instance, a 
man, a dog, and a horse, all moving swiftly with a pecul- 



Sec. 2.] Principal Processes. 101 

iar step, and we denote this kind of motion by the term 
running. The process of naming usually follows the dis- 
covery of the general attribute : but it is no essential 
part of it, and properly belongs to what is termed classi- 
fication, of which we shall treat hereafter. 

By this method we generalize regarding all that we 
have actually comprehended, which constitutes empiri- 
cal generalizations, or empiricisms : but to pass beyond 
these, to scientific generalizations, or inductions, requires 
other methods. 

An empiricism is, a generalization which includes only 
cases actually experienced. An induction is, a general 
ization which is proved to extend to the whole class to 
which it relates. " All the horses that I ever saw, were 
four-footed," is an empirical, and "all horses are four- 
footed," is an inductive, proposition. To establish an in- 
duction, it is requisite, not only that all the things ob- 
served should harmonize with it, excluding only such as 
are mere exceptions to the general rule, but that we have 
some satisfactory reason for extending the empiricism to 
the whole class, in which case alone it becomes a scien- 
tific generalization. 

In comparing external objects, some or all may be ab- 
sent : for the ideas of them furnished by Memory, if suf- 
ficiently distinct and accurate, answer the same purpose 
as the original perceptions. In comparing, we only ob- 
serve two or more things simultaneously, and examine 
their agreements or differences, by the aid of Abstrac- 
tion : and hence the faculty of Comparison is only a com- 
bination of Comprehension and Abstraction. 

2. As the same conditions or agents, operating in the 
same circumstances, must always produce the same re- 
sults, we generalize regarding these by ascertaining what 
they are in one instance. Thus, if we find, by experi- 
ment, that a certain degree of heat has melted iron, we 
know the inductive proposition that such a degree of 
heat melts iron. 

In investigating the facts of the particular instance, 
continued observations or repeated experiments are 
sometimes requisite, in order to ascertain the real condi- 
tions or results : for, if we had only one example, a doubt 
might arise whether a result was not dependent, at least 
in pai*t, on other conditions ; and, therefore, it is neces- 
sary to continue our researches, till we have ascertained 



102 Generalization. [Chap. V. 

the real conditions or results. But where there is no 
room for such doubts, one observed case is sufficient. 

3. By taking a particular object, and reasoning from 
those attributes which it. possesses in common with all 
others of the same class, we arrive at conclusions which 
hold equally true of the whole class, on the principle, al- 
ready stated, that conclusions established independently 
of certain peculiarities, are not affected by any change 
in these peculiarities. Thus, to prove that " the square 
of the hypothenuse of every right-angled triangle is equal 
to the squares of the two sides containing the right an- 
gle," we take any right-angled triangle, and prove that 
its sides have this property, independently of its partic- 
ular form, size, color, or position : and then, as the rea- 
soning is independent of these peculiarities, we know 
intuitively that the conclusion holds equally true of all 
triangles which agree in being right-angled, however 
much they may differ in other respects. So a multipli- 
cation table is constructed by first counting certain num- 
bers of particular objects ; and as the amounts must al- 
ways be the same, as long as the numbers are the same, 
the results hold true universally. 

Inductions regarding nature are established in the 
same way. Thus it is shown that " whales are mammals, 
and not true fish," by examining a single whale, and find- 
ing that it breathes air, has a double heart, with warm 
blood, and suckles its young, which are the essential 
characteristics of mammals. As all whales have these 
peculiarities, the particular species examined, its size, age, 
and so forth, are matters that do not, in the least, affect 
the truth of the conclusion. 

By this means we make an individual represent the 
whole class to which it belongs; and thus, without act- 
ually examining more than a few individuals, we obtain 
a knowledge of properties common to the whole class. 

4. In the preceding case, it was assumed that every 
individual of a class has certain attributes in common ; 
and we now inquire how this is known. 

With respect to such attributes as are embraced in 
the definition of the class, they must evidently possess 
these; otherwise they would not belong to it. Every 
right-angled triangle must have a right angle ; and every 
pei-fect quadruped must have four feet; otherwise it 
would not be a quadruped. But nature is independent 



Sec. 2.] Principal Processes. 103 

of our definitions ; and, therefore, we must look beyond 
these, in order to generalize satisfactorily regarding other 
attributes. 

"We first observe several of a class, till we are satisfied 
that the properties which they possess in common, are 
not owing to individual peculiarities or malformations ; 
and we then infer the generality of these properties from 
the nature of the agencies which operate to produce 
them. 

We know, from the phenomena which everywhere 
present themselves to our view, that the same agencies 
operate throughout the visible creation. Hence it fol- 
lows, from the principles of causation, that the same reg- 
ularity and uniformity prevail in things not observed, 
which have been found in those actually examined : oth- 
erwise effects would occur without adequate causes, and 
different effects would result from the same agencies, op- 
erating in the same circumstances. Thus, men now pos- 
sess essentially the same physical constitution that be- 
longed to the dead, because they have the same origin ; 
and they are surrounded and influenced by the same 
agencies : hence we justly infer that the living will all 
die, like their forefathers. As the circumstances and 
agencies are the same, the results must be the same ; and 
thus we arrive at the induction that " all men are mor- 
tal." A better observance of the laws of health will pro- 
long the average duration of life : but it cannot essen- 
tially alter our physical constitution, or wholly neutralize 
the action of the various causes which operate to destroy 
it, so that all the differences in the circumstances and 
conduct of individuals, only affects the time when they 
will die. 

This process is applicable only to the ordinary course 
of events, with which it assumes that no extraneous or 
peculiar agency interferes. But the Deity may occa- 
sionally, for special and important reasons, adopt a pe- 
culiar and extraordinary mode of proceeding, contrary 
to the usual course, or allow certain extraneous or un- 
usual agencies to interfere with the ordinary results : 
and the occurrence of monsters shows that the latter 
supposition is true. Hence it is only in reasoning from 
intuitions, hypothetical assumptions or abstract defini- 
tions, that our inductions are rigidly and universally true. 
Yet, as the Most High is eternal, immutable, omnipotent, 



104 Generalization". [Chap. V. 

omniscient and supremely benevolent, he can never act 
from caprice, ignorance, weakness, malice, or any new 
resolve. Hence exceptions to the general laws of nature 
must be of very rare occurrence, so that they detract 
nothing from the practical or scientific value of induc- 
tions. The unconformable cases are only very rare ex- 
ceptions to a general rule; and the circumstances in 
which even these occur, frequently enable us to know 
that a particular case is no exception. 

The divine character informs us that the same uniform- 
ity and harmony which we now behold, must have pre- 
vailed since the present order of things began, and will 
continue till its termination, which appears, by various 
proofs, to be still very distant. But our inductions re- 
garding nature do not extend to what may have been, 
before the present order of things began, or to what will 
be, after this planet has ceased to revolve in its accus- 
tomed orbit : and even within these limits, there are few 
physical inductions which have no exception. Most sub- 
stances have weight ; but light, heat and electricity have 
none : ponderable substances generally tend to move to- 
wards each other ; but excited electrics, the similar poles 
of two magnets, and the parts of all compressed elastic 
bodies, including gases, are repelled from each other : 
and fluids generally contract, as they cool ; but water 
near the freezing point is an exception. 

Where a phenomenon is the result of a constant and 
uniform agency, its generality is proved by showing the 
existence and nature of the cause. When we trace the 
changes of day and night, and the succession of the sea- 
sons, to the two motions of the Earth, we discover that 
those phenomena are as constant as the course of nature ; 
and the uniformity and stability of this is shown in the 
manner just indicated. Thus are established such gen- 
eral propositions as — "day follows night" — "summer 
follows winter" — &c, which will hold true till the Sun 
ceases to shine, and the Earth to move, as they now do. 

The constancy and uniformity of nature has been fre- 
quently assumed from its having been observed by a very 
narrow experience, without any clear or thorough knowl- 
edge of its real foundations : and hence has resulted the 
error of the individual making his own experience and 
views a standard for determining the laws of nature. 
These can never be logically established without a refer- 



Sec. 2.] Principal Processes. 105 

ence to the character of the Author and Ruler of nature. 
This is ascertained from particular facts or empirical 
generalizations ; and, when once ascertained, it is appli- 
cable to establish, not only the general uniformity and 
stability of nature, but innumerable inductions regarding 
particular phenomena. Although not always expressly 
mentioned, it is always referred to in such cases : other- 
wise certainty would be unattainable ; and we could es- 
tablish only probabilities. An atheist cannot logically 
establish any physical or mental science, without assum- 
ing propositions which directly contradict the essential 
peculiarities of his creed. 

In distinguishing specific or generic from individual or 
accidental peculiarities, we are aided by knowing that 
certain properties are essential to the perfect structure 
or well-being of a class, while others are not, even al- 
though they may have been found common to every one 
of a class hitherto known. Hence the character of the 
Deity proves that the class must possess the former, 
while many of its species or individuals may lack the 
latter. A traveler of ordinary veracity would be enti- 
tled to credit, if he should relate that he had discovered, 
in some hitherto unexplored region, a new species of 
crows which were white, or a breed of sheep as small as 
rabbits : for color and size do not affect the well-being 
of a species, whose individuals often differ widely in these 
respects. But, if he should further relate that he had 
discovered a species of bird which spent the winter in a 
dormant state, under water, or a kind of sheep which 
lived exclusively on flesh, we should have good reason to 
conclude that he was either mistaken or desired to mis- 
lead. For such animals could not endure, without a per- 
petual miracle ; and, therefore, we might justly infer that 
the Creator never formed such beings. 

Among the properties common to animal species, may 
be reckoned the structure of the nervous system, bones, 
muscles, blood vessels, organs of sense, and digestive ap- 
paratus. In vegetables the bark, the wood, and the form 
and arrangement of the branches, leaves, flowers and 
seeds, are always alike in a species. In inorganic bod- 
ies, the individual attributes are generally common to 
the species, except form and magnitude, although there 
are some striking exceptions. One piece of pure iron or 
lime is distinguished from another chiefly by its form 
E 2 



106 Generalization. [Chap. V. 

and size. In crystals, even the form is uniform, in the 
various species. 

A moderate acquaintance with the general structure 
of organic beings, and the harmony of their parts, in a 
normal state, enables us to detect anomalous productions, 
with little difficulty. A naturalist who had. previously 
known nothing regarding the horse, would readily see 
that one with only three legs wanted a limb, while one 
with five had a superfluous organ. He has abundant 
proofs that the Ruler of nature is able to render every 
being harmonious and perfect in its organization ; and, 
therefore, when he finds some manifest deviation from 
that harmony and perfection, he justly infers the being 
is of monstrous or defective formation, and by no means 
a normal representative of its species, while, on the oth- 
er hand, a perfect specimen is known by its exhibiting 
no such deviations. 

All inductions are established by means of the prin- 
ciples regarding determining conditions and agencies 
stated in Chapter II. ; and all the processes consist sole- 
ly of ordinary reasoning. They are only inferences more 
comprehensive than the premises. We infer that a prop- 
osition known to hold true in a few individual cases, is 
equally applicable to the whole class to which these be- 
long. We may reason from probable, as well as from 
certain, premises ; yet this does not affect the nature of 
the process, which is as uniform as that of sight or hear- 
ing, whether the subject be Mathematics, Physics or Met- 
aphysics. The only difference is, that the individual is a 
perfect representative of a class, which are all alike, in one 
case, but not always so, in others. If we had a horse, 
which was as like every other horse as one right-angled 
triangle is like another, we could demonstrate the prop- 
erties of every horse as conclusively as it is proved that 
the squares of the sides containing the right-angle are to- 
gether equal to the square of the side opposite. 

Intuitions are known to be true by direct conscious- 
ness, even when they are stated in a universal form ; and, 
therefore, they require no process of generalization, while 
it is by their means alone that we ascend from the par- 
ticular facts of comprehension to a knowledge of general 
contingent truths. 

It is not the number of observed cases which consti- 
tutes an induction, but the proof that the observed attri- 



Sec. 3.] Extension of Generalization. 107 

bute is general, which requires that there be no uncon- 
formable cases, except such as are anomalous or irregu- 
lar. Although new-year's day should be found to have 
been stormy, for ten years in succession, this would not 
establish it as an induction that it is always so, whereas 
the chemical decomposition of a substance, in a single 
instance, may establish its composition as an inductive 
truth. In the former case, there is only a fortuitous co- 
incidence, while, in the latter, the previously discovered 
laws of chemical composition exclude such a supposition. 
It is even possible that all the obseiwed cases may be 
contrary to the induction, as where a person who has 
never seen a normal individual, is shown a number of 
monstrous or diseased specimens collected by a friend. 
So one who never saw any horned animal except Shet- 
land sheep, might imagine that three or four horns is the 
usual, whereas it is the exceptional, number. (13) 

§ 3. Extension and Uses op Generalization. — Superior and Sub- 
ordinate Generalizations. — Mode of establishing the latter, and why 
they are usually discovered first. — Use of Empiricisms and of In- 
ductions. — Advantages of extending Generalization. — Empiricisms 
distinguishable from Laws of Nature. — Evils arising from confound- 
ing them. 

In the progress of science, it is often found that gener- 
alizations which were formerly considered ultimate and 
independent, are only particular cases of a more general, 
law, or common effects of the same agency. In such 
cases, the more general law is termed the superior or 
higher, and the more particular law or effect, the subor- 
dinate or special law. The law that " terrestrial bodies 
tend towards the center of the Earth," and that "the 
planets tend towards the center of the Sun," are only par- 
ticular cases of the law of gravitation. 

The processes by which we ascend from the subordi- 
nate to the higher laws, are similar to those by which we 
establish the former. But, as the higher include many 
particular cases, a wider range of observation is general- 
ly requisite, and the connecting points are not so easi- 
ly ascertained. Hence subordinate laws are usually the 
first discovered. In some cases, however, this order is 
reversed. The doctrine of gravitation was established 
before anything was known regarding many of its sub- 
ordinate laws. As the general includes the particular, 
the establishing of the superior implicitly establishes all 



108 Geneealization. [Chap. V. 

its subordinate laws ; but these are not explicitly estab- 
lished, till they are specifically known. 

Empirical generalization is necessary, in order to our 
remembering and reasoning about any considerable num- 
ber of the countless multitude of objects which fall un- 
der our notice : for, if we attempt to view every indi- 
vidual as an isolated whole, and do not attend to those 
points in which it resembles others, we shall be confound- 
ed, amid such a chaotic maze, and our reasoning will be 
confined, in a great measure, to individuals. The diffi- 
culty is surmounted by forming empiricisms, which ena- 
ble us to investigate an individual as a proper represent- 
ative of a class, and to comprise many particulars in gen- 
eral propositions. 

Empiricism is also, in many instances, a necessary pre- 
liminary to induction, which is requisite in order to our 
performing many of the duties of life, since experience 
teaches us nothing regarding the future, or that wide 
and important part of nature to which our experience 
has never extended. Hence we must go beyond empir- 
icisms, in order to know what will result from certain 
circumstances, or what we shall find, immediately beyond 
what we now comprehend. 

The advantages of extending our generalizations, so 
as to include as many particulars as possible, are much 
greater than we might expect. Not only is the Memory 
assisted, by being freed from the necessity of retaining 
a great variety of special generalizations, but the path to 
knowledge is rendered shorter and more secure, while 
the results are frequently more abundant. For we have 
only to deduce all the logical consequences of the gener- 
al principle, in order to establish them as truths, instead 
of performing many independent investigations, and fre- 
quently relying on doubtful observations or testimonies. 
Thus, the laws of motion and gravitation enable the in- 
vestigator of nature to establish a great number of im- 
portant laws in the physical sciences, many of which 
would otherwise require treble the labor, or could not 
be established at all. 

Another great advantage of extensive generalization 
is, that it enables us to take a wider view of the rela- 
tions which things bear to each other, without which a 
knowledge of special laws is sometimes of comparatively 
little avail. For, as these often result from a more gen- 



Sec. 3.] Uses of Generalization. 109 

eral law, the power which we derive from a knowledge 
of the latter, is as much superior to what we could ob- 
tain from a knowledge of special laws, as the power of 
permanently stopping a fountain is greater than that of 
drying for a time one of several rills, while their common 
source continues to flow. If we could discover the cause 
of some deadly epidemic, and an effectual means of re- 
moving it, this would be of much more consequence than 
the discovery of a medicine which would cure only some 
forms of the disease. 

The extension of induction is of much importance, in 
many instances, by exhibiting a greater variety of means 
for effecting the same end. By obtaining, for example, 
a more general view of the causes which produce a par- 
ticular effect, we are frequently furnished with a variety 
of agents for accomplishing the same end, so that when 
one is not within reach, we can employ the other. 

We should carefully distinguish empiricisms from laws 
of nature, which are always the expression of an induc- 
tion, because much evil has arisen from confounding the 
two kinds of generalization. The mere fact of our hav- 
ing found a certain uniformity prevailing within the range 
of our observation, does not warrant us in assuming that 
this uniformity holds throughout nature, unless this can 
be established by some satisfactory proof. Many lives 
have been lost, owing to medical empiricisms being mis- 
taken for inductions, and physicians consequently adopt- 
ing an improper course of treatment, because it had been 
found beneficial in other cases, apparently similar but 
really different. 



CHAPTER VI. 

OF HYPOTHESES. 

§ 1. Nature and ttses of Hypotheses. — Definition of Hypotheses. 
— Their general value. — Why their importance frequently over- 
looked. — How they promote close and careful investigation. — In- 
dispensable, in many cases. — Their importance as guides. — How 
they aid Memory and Classification. — Such uses independent of 
their correctness. — Use of Hypotheses partially incorrect. — Refu- 
tation of objections. — Application to things inconceivable. — Use of 
Hypotheses in common life. — Abuse of Hypotheses. 

An hypothesis is, a supposition, made on a subject of 
which we have some knowledge, regarding something 
still unknown, which we desire to find out. 



110 Hypotheses. [Chap. VI. 

Wherever the character of the proposition in question 
cannot be ascertained by direct observation, experiment, 
or reasoning, we must form an hypothesis, and then pro- 
ceed to test its truth. The importance of this course is 
evinced by the history of the physical sciences, many of 
whose truths could have been discovered by no other 
means. 

The confirmation frequently given to established hy- 
potheses by subsequent discoveries, is apt to make us 
overlook the means by which they were first proved, be- 
cause all other suppositions now appear so baseless that 
we foi-get some of them once appeared more plausible 
than the true. When this has been ascertained, the dis- 
coverer often confines himself to the proofs in its favor, 
without informing us of the means by which he first 
made the discovery. 

Hypotheses indirectly aid the progress of discovery by 
their leading to close discussions and extensive observa- 
tions and experiments : for their authors and upholders 
exert themselves to ascertain facts which may confirm 
their own views, and to detect misstatements or fallacies 
on the part of their rivals, while the latter follow a sim- 
ilar but adverse course. 

In many inquiries, hypotheses are both unavoidable 
and indispensable, because the apparent differ widely 
from the real facts, while the latter can be ascertained by 
no direct means. When we view the heavenly bodies, 
for example, we must form some supposition regarding 
their real motions; and we can determine these from 
their apparent motions, only by making several supposi- 
tions, and ascertaining which is the true one. In all 
cases of this kind, it is impossible to think of the subject 
at all, without forming an hypothesis, until some partic- 
ular hypothesis has been established. 

In some cases, hypotheses, although not indispensable, 
are of great importance, because they enable us to ascer- 
tain what course is likely to succeed, and what not. 
Hence much time and labor, are saved, which would oth- 
erwise be wasted to no purpose. For, by considering 
the various admissible suppositions, and their relative 
degrees of probability, we shall ascertain the truth much 
more readily than if we proceeded without any guidance. 

Hypotheses also aid Memory, and assist us in classify- 
ing a great variety of phenomena, according to some 



Sec. 1.] Uses oe Hypotheses. Ill 

logical principle, and ascertaining their relations to each 
other. The observable phenomena of many subjects are 
so numei'ous, and apparently so unconnected, that we 
can remember and classify the facts and their manifest 
relations to each other, only by forming some supposi- 
tions regarding their causes and connections. Thus, the 
classification of the various divisions of organic nature, 
the remembrance of the peculiarities of each, and a 
knowledge of their relations, are greatly facilitated by 
supposing some archetype or general model, which was 
variously modified, in order to produce the different 
classes, and adapt them to specific modes of living and 
acting : for we can thus most easily understand and re- 
member the characteristics of every kind, and what rela- 
tions it bears to others ; after which a proper classifica- 
tion becomes comparatively easy. 

Such uses of hypotheses are quite independent of their 
correctness. Thus, in the case just mentioned, the sup- 
position that the Creator took some form as a model, and 
©variously modified it, to produce the different classes, is 
not only destitute of proof, but most probably false. Man 
requires such helps, to produce a variety of similar forms ; 
but we have no reason to believe that the Deity needs 
any such aid. Yet it is nevertheless true that the vari- 
ous classes are formed as if such a model had been em- 
ployed ; and, therefore, the supposition is as useful for 
the purposes just mentioned as if it were actually true. 

The Ptolemaic system of Astronomy is another in- 
stance of this kind. Although fundamentally erroneous, 
it served to introduce some degree of system and order 
into the complex phenomena of the heavenly bodies ; and 
some of its suppositions are so convenient, for several 
purposes, that they are still retained in various opera- 
tions, although they are well known to be false. 

If an hypothesis fundamentally erroneous may be use- 
ful, much more may one which is only partially untrue, 
and correct in the main, such as the views of Copernicus 
regarding the motions of the planets. He was right in 
supposing that the Sun was comparatively at rest, in the 
center of the system, with the planets revolving round it ; 
but he erred in supposing that they moved in epicycles. 
This hypothesis accounted for most of the phenomena 
then known ; and its errors were such as could not fail 
to be detected by further observations, made with better 



112 Hypotheses. [Chap. VI. 

instruments than those of that age. An hypothesis fun- 
damentally correct generally indicates the course to he 
adopted in testing its details ; and hence the principal 
difficulty is usually surmounted as soon as such an hy- 
pothesis has been established, although it may be erro- 
neous in several minor details. 

Hypotheses also enable us to refute objections urged 
against a proposition of whose truth we have satisfactory 
evidence. We meet the objection by showing what may 
be, even when we cannot prove that such is actually the 
case. 

By means of language, hypotheses further enable us to 
transcend the powers of Conception, and thus to discuss 
things inconceivable or impossible : for we can suppose, 
for the purposes of argument or examination, whatever 
can be expressed in words. Thus, although we cannot 
conceive of an endless series of events, or an eternal be- 
ing, we can reason about them, as long as our reason- 
ings do not require us to form any conception of them. 
Much of the utility of hypotheses arises from this powei^ 
of applying them to any proposition : for, in many in- 
stances, it is only by investigating and testing all the pos- 
sible kinds of suppositions regarding the subject under 
consideration that we can determine which is the true 
one. 

As the term hypothesis is most frequently applied to 
suppositions on scientific subjects, we are apt to overlook 
their great importance in common life. Yet this is not 
the less real. In all those cases where we have to choose 
between several practicable courses, we may suppose 
them successively adopted, and trace the several advant- 
ages and disadvantages attending each, after which we 
can compare these, so as to adopt the most eligible. In- 
calculable evils have arisen from either totally neglecting 
this process, or performing it very hurriedly and inaccu- 
rately. We are often so anxious to act, and so impa- 
tient of delay, that we overlook the serious disadvantages 
of the course we adopt, and the much greater advantages 
of another. Hypotheses of this kind are often employed 
without the individual being aware of it, because they 
are made, and conclusions di-awn from them, with such 
extreme rapidity that these are taken for immediate dis- 
cernments. 

Hypotheses are liable to the great abuse of adopting 



Sec. 2.] Testing Hypotheses. 113 

them as established truths, while they are only plausible 
suppositions. Before adopting or admitting any hypoth- 
esis as a truth, it should first be conclusively established 
by proof. 

§ 2. Methods of testing Hypotheses. — Tests of mathematical and 
some other Hypotheses. — Four characteristics of correct Hypothe- 
ses regarding Phenomena. — When a phenomenal Hypothesis is es- 
tablished. — Theory. — Principal means of testing phenomenal Hy- 
potheses. — Effects of increased knowledge. — Anticipation of future 
discoveries. — How erroneous Hypotheses are sometimes exploded. 
— Influence of discoveries in other departments. — Superior kind of 
Hypotheses. — Cautions. 

In many cases, hypotheses are proved by simply find- 
ing that they are necessarily implied in something al- 
ready known to be true ; or they are disproved by our 
discovering that they involve errors or absurdities. It 
is by such means that all mathematical hypotheses are 
tested ; and the same processes are often applicable in 
other cases also. Thus, the hypothesis that nature ab- 
hors a vacuum, is disproved by the fact that a vacuum 
occurs wherever there is no force in operation to fill it. 

To establish an hypothesis regarding phenomena as a 
truth, it must possess the four following characteristics. 

1. The phenomena or appearances which it is employ- 
ed to prove or explain, must be real or actual, and not 
merely supposed or assumed. 2. It must not be incon- 
sistent with any cognition. 3. It must account for all 
the phenomena in question. 4. It must be the only hy- 
pothesis which possesses the second and third character- 
istics. 

If we overlook the first of these conditions, we attempt 
to account for what may have no existence ; and we may 
only strengthen error by withdrawing attention from the 
nature of our assumptions. The second condition is req- 
uisite to render the hypothesis correct, so far as it goes. 
The third is necessary to render it complete : for an hy- 
pothesis which accounts only for some of a group of con- 
nected phenomena, must be at least defective. The 
fourth condition is necessary in order to exclude other 
hypotheses : for, if one accounts for all the facts as well 
as another, and contains nothing inconsistent with known 
truth, it is as well entitled as any to be received as cor- 
rect. 

When a phenomenal hypothesis has been proved to 



114 Hypotheses. [Chap. VI. 

possess those four characteristics, it ceases to be an hy- 
pothesis, and becomes a cognition : and if it consists of 
a fundamental principle, or series of such principles, it is 
termed a theory, which implies something put forward as 
a truth, and considered such by the propounder, although 
it may not, in reality, be satisfactorily established. 

The principal means of testing phenomenal hypothesis 
are, extended observation and experiment. An hypoth- 
esis may possess the three first of the above character- 
istics when it is formed : but the progress of discovery 
may refute it, by disclosing facts incompatible with it, as 
happened with the Ptolemaic system of Astronomy. 

While an erroneous hypothesis is generally detected 
by more extensive researches, a correct theory receives 
confirmation from new discoveries. Thus, the aberration 
of light, which directly proves the motion of the Earth 
in its orbit, was discovered by Bradley, in the eighteenth 
century, nearly two hundred years after the death of 
Copernicus : and, of the lunar irregularities now deduced 
from the law of gravitation, more than three fourths were 
unknown to Xewton, who established that doctrine. 

A correct hypothesis not only accounts for new facts, 
after they have been discovered, but it frequently enables 
us to conjecture them beforehand. Thus, the theoretical 
astronomer has often made discoveries in his study, which 
were afterwards verified in the observatory. An erro- 
neous hypothesis, on the other hand, is liable to be ex- 
ploded by a single observation or experiment. Thus, 
the hypothesis that dew emanates directly from the 
ground, is exploded by seeing it copiously deposited on 
a piece of iron. 

An hypothesis is frequently confirmed or refuted by 
discoveries made in other departments than that to which 
it refers. Thus, the establishment of the undulatory 
theory of light explodes the material theory of heat ; 
and the progressive motion of light is proved by observa- 
tions on the eclipses of Jupiter's satellites. 

In determining which of several admissible hypotheses 
is the true one, we are often assisted by a knowledge of 
the nature of the various agencies which may possibly be 
concerned in producing the phenomena under considera- 
tion, without further recourse to observation. Tims, the 
force of gravitation accounts for the ascent of mercury in 
the tube of the barometer, and of water in the suction 



Sec. 2.] Testing Hypotheses. 115 

pipe of a pump, so that we may at once discard the hy- 
pothesis of nature's abhorrence of a vacuum, or of a pow- 
er of suction in the tube. 

Of two hypotheses, otherwise equally probable, that 
which traces phenomena to a real agency, is entitled to 
a preference over one which attributes them to some un- 
known cause. For the Ruler of nature has never been 
found employing two different agencies when one would 
accomplish all the results equally well. But in those 
cases where unknown agencies may possibly interfere 
with the results deducible from a certain hypothesis, these 
ought to be investigated : for otherwise we know not 
how far such agencies may interfere ; and the hypothesis 
is not legitimately established till it has stood this test. 
Thus, the actual path of a projectile through the air, is 
very different from what is deduced from an hypothesis 
that overlooks the atmospheric resistance. A cannon 
ball, fired off at a certain angle of elevation, will go less 
than the twentieth part of its range, if it moved in a 
vacuum. 

Before applying hypotheses, we should ascertain that 
we have a clear and accurate knowledge of the facts in- 
volved : for, if our views of these are confused or errone- 
ous, the use of hypotheses will be apt to mislead us, and 
confirm us in erroneous opinions. 

We should also beware of adopting any hypothesis, 
however plausible, as a truth, until we obtain decisive 
proof; and we should discard it whenever we have ob- 
tained satisfactory evidence that it is erroneous. 



PART II. 

OF THE PRINCIPLES AND METHODS OP 
INVESTIGATION. 



CHAPTER VII. 

OF INVESTIGATION IN GENERAL. 

§ 1. Of Dispositions affecting Investigation. — Common Error. 
— Advantage of Equanimity. — Two Extremes. — Their common 
Origin. — Proper Medium. — Diversity of Opinions. — On what our 
Attainments chiefly depend. — Eequisites to successful Investigation. 
— How the proper Disposition is to be secured. 

The investigation, even of the most important sub- 
jects, is frequently conducted in such a way as to be 
worse than useless : for it satisfies the individual that he 
now knows enough on these topics, and thus stifles fur- 
ther inquiry, while it substitutes positive unconscious er- 
ror in the place of conscious ignorance. In order to act 
more warily, we must see the necessity for distrusting 
the correctness of opinions adopted without carefully ex- 
amining the foundations on which they rest. 

If the mind is strongly affected by some emotion, while 
we are examining a subject, it will both distract the at- 
tention, and prevent us from taking a sufficiently close 
and extensive view of the subject, so that some import- 
ant points will be considered inattentively, and others 
will be wholly overlooked. We should, therefore, ab- 
stain from investigation, till we are disposed to consider 
it attentively, and without any passionate emotion : oth- 
erwise we shall only fortify ourselves in error. 

Many have assumed that truth is very easily discov- 
ered, and that men fall into ei'ror owing to some defect 
or depravity from which they considered themselves en- 
tirely free. This state of mind leads to adopting, with- 
out any proper examination of their real nature, the first 
plausible opinions that force themselves on the attention, 
if not opposed to the party's prejudices, retaining them 
with unreasonable pertinacity, and contemning every con- 
trary view. 

Many have fallen into the opposite extreme. They 
have seen the great diversity of opinions that has pre- 
vailed, even among the more intelligent portions of man- 
kind : and hence they concluded that truth must be very 



120 Investigation in General. [Chap. VII. 

hard to discover, or that it cannot matter much whether 
we discover it or not. This class delight in caviling ob- 
jections, and in oppugning all the foundations of knowl- 
edge : they draw futile distinctions, while they overlook 
important differences, and oppose to one set of opinions 
the objections urged by the disciples of another, without 
ever carefully examining whether they are valid or worth- 
less. 

Those two extremes both originate from an erroneous 
opinion regarding the human faculties, and an unwilling- 
ness to undergo the labor of proper investigation, com- 
bined with various other prejudices and prepossessions. 
Hence it frequently happens that the same individual is 
very sceptical regarding disagreeable truths, and equally 
credulous and dogmatic regarding agreeable errors. 

The proper disposition avoids each of those extremes : 
it is ready to investigate aright the arguments in favor 
of any opinion which really deserves or requires investi- 
gation, and to adopt it, if these be found conclusive, 
while, on the other hand, it is prepared to reject every- 
thing which is refuted by irrefragable proof. 

The great diversity of opinions which has prevailed 
among mankind, shows that truth is not to be discov- 
ered without proper investigation : yet all the most im- 
portant truths are placed within the reach of ordinary 
abilities ; and persons of greater talents fail to discover 
them, only when they never search for them aright. The 
young inquirer must not imagine that certainty is unat- 
tainable, even where he finds conflicting opinions held 
by distinguished men. Investigators whose principal 
object was gain, applause, victory, or the gratification of 
some darling prejudice, could not reasonably be expect- 
ed to discover truth ; and we cannot rightly attach any 
weight to the opinions of the many who have either 
adopted the views of others, without ever bestowing on 
the subject an independent examination, or who have 
formed opinions of their own, without having ever in- 
vestigated it with care and attention. 

Our attainments depend much more on the use we 
make of our faculties than on their natural force ; and 
truth is reserved for those who discard prejudices, and 
seek it with proper care and diligence, without which 
great abilities only generate self-conceit, indolence and 
error. If it were more easily attainable, it would be less 



Sec. 2.] Dispositions. 121 

valued, and sought more negligently and indolently, 
whence error would abound more than it does. Al- 
though the path of the faithful inquirer may at first ap- 
pear gloomy, yet the dark clouds raised by ignorance 
and misconception rapidly vanish, as he advances, and ce- 
lestial radiance then cheers and guides his course. 

In order to successful investigation, the following 
things are requisite. 1. A correct estimate of the 
value of truth, and of the sacrifices which must be made 
for its attainment. 2. A mind prepared to examine 
properly every important subject, and adopt whatever 
conclusions truth dictates. 3. A correct estimate of 
our own capabilities. We must neither think that we 
can secure truth without a careful, continued and impar- 
tial examination, nor that it is placed beyond the reach 
of ordinary abilities perseveringly and judiciously ap- 
plied. 4. A patient and active disposition, that we may 
neither adopt a conclusion till we have sufficiently exam- 
ined the subject, nor hesitate to investigate carefully and 
diligently all subjects having an important bearing on 
our welfare. 

The disposition proper for investigation is to be at- 
tained by acquainting ourselves with the value of knowl- 
edge, and the evils of ignorance and error, the sources 
of error, and the requisites to successful investigation. 
For this will produce an earnest desire to secure truth 
and avoid error. 

§2. Of Habits affecting Investigation. — General influence of 
Habits. — (1) Attention and Inattention. — (2) Methodical and de- 
sultory Application. — Advantages of a general Plan. — Caution. — 
(3) Wide and narrow views of the subject. — Evils of superficial 
and partial views. — (4) Properly investigating Proofs, and jump- 
ing at Conclusions. — (5) Activity and Perseverance. — Evils of In- 
dolence and Indifference. — Important Laws. — (6) Eesisting Prej- 
udices. — Results of being led by our Wishes. — (7) Temperance and 
Self-Control. — Connection of Habits. — Evils of Self Indulgence. — 
How good Habits are to be formed. 

Habits sway our conduct so extensively that, in order 
to successful investigation, we must form such as are fa- 
vorable to that result, and avoid those of a contrary kind. 
We shall, therefore, consider the former, and notice those 
which are opposed to their influence. 

1. We have already seen that all erroneous opinions 
are traceable to inattention, as their immediate source : 

F 



122 Investigation in General. [Chap. VII. 

and it also requires close attention, in many cases, in or- 
der to discover the properties of things, or their relations 
to each other. Hence the habit of close attention to the 
subject under consideration is necessary to guard us 
against adopting errors, and enable us to go beyond the 
simple elements of knowledge. It is opposed to the habit 
of considering a subject carelessly, or while our attention 
is, at the same time, fixed on something else, a course 
which inevitably leads to serious errors. We should, 
therefore, beware of tormenting ourselves about small 
matters and imaginary evils, and guard against the prac- 
tice of skimming along the subject that we are consider- 
ing, without devoting to any part more attention than it 
excites spontaneously: otherwise we cannot, without 
great difficulty, concentrate our attention, even for an 
hour, on any subject. 

2. Several subjects, of the highest importance, cannot 
be rightly understood without a continued degree of at- 
tention. Truth is not generally discovered at a glance, 
but only by a long examination, and considering the sub- 
ject again and again. Now if we rove from one sub- 
ject to another, without devoting sufficient time and at- 
tention to each, our thoughts become more or less con- 
fused, so that, when we return to the subject whence we 
deviated, we hardly know where we left off, and find that 
we must begin again at the starting-point. Hence our 
progress will be very slow and unsatisfactory. Not un- 
frequently the attention will be so occupied with the sub- 
jects previously considered, that careful examination is 
impracticable, various things widely different are con- 
founded with each other, and many errors inevitably re- 
sult. 

In order to avoid these evils, we must acquire a habit 
of considering, at the outset, the scope and object of our 
investigations, and of contimied and methodical applica- 
tion. This is opposed to the habit of flying from one 
subject to another, and talcing up anything which strikes 
the fancy of the moment, without any definite aim or ob- 
ject, which leads to much time being spent with no oth- 
er result than acquiring many erroneous opinions, and a 
habit of relinquishing an investigation as soon as it has 
lost the charm of novelty. Thus we come to wander 
from one subject to another, without learning more of 
any than suffices to make us conceited, and satisfied with 



Sec. 2.] Habits. 123 

the mere husks of knowledge, while our views may be, 
in many respects, very erroneous, and we may be ignor- 
ant of the more important parts of the various subjects 
over which we have been flying. 

We should form a general plan, which devotes a rea- 
sonable time uninterruptedly to the various subjects of 
our investigation, from which we should not deviate 
without some urgent and justifiable motive, nor farther 
or longer than the circumstances warrant. We are gen- 
erally surrounded by temptations to turn aside from in- 
vestigation to things which are immediately more at- 
tractive, especially to persons who do not look beyond 
the present moment, nor consider the tendency of desul- 
tory habits, and occupying the attention with matters of 
no real consequence. Yielding to enticements of this 
kind has been a fruitful cause of unsuccessfulness, among 
those who have desired and attempted to succeed in the 
pursuit of truth. 

We may investigate more than one subject to advan- 
tage, in the course of the day. But, in order to this, we 
must devote a considerable time to each, and not run 
desultorily from one to another. Increasing knowledge 
may suggest improvements in our plan, as we advance : 
but we should beware of proceeding without plan or ob- 
ject, which we shall inevitably do, unless we consider the 
precise drift and purpose of our investigations. If we 
fail to do this, we shall often begin an investigation, and 
never finish it, whence we readily slide into the habit of 
dipping into every kind of subject, without ever acquir- 
ing a solid knowledge of any. 

We should, therefore, arrange our thoughts and ma- 
terials in the most regular manner practicable, and not 
take leave of the subject until we nave done our best 
to master it. Otherwise we shall fall into confusion of 
thought, and abandon a subject before we have begun 
to understand it. Our investigations may be frequently 
interrupted by things beyond our control : but this need 
not prevent us from returning to the subject when the 
cause of the interruption ceases ; and the habit of doing 
so is requisite in order to understand any subject thor- 
oughly. 

3. The habit of viewing the subject in its various bear- 
ings, and ascertaining its real character, is necessary to 
prevent us from overlooking points of great importance 



124 Investigation in General. [Chap. VII. 

or attaching undue weight to those which we have con- 
sidered, to enable us to see everything in its true light, 
and to know the value and application of our attainments. 

This habit is opposed to that of forming conclusions 
before we have rightly examined the whole subject, or con- 
sidering only one of several important bearings, and over- 
looking the rest. This leads to the numerous evils inci- 
dent to superficial or partial views, which frequently mis- 
lead as effectually as positive error, an omission being as 
fatal as a false addition. It also leads us to overlook the 
recondite and future bearings of a question, which are 
frequently very different from the obvious and present 
aspects, and of incomparably more importance. This er- 
ror is one of the most common and pernicious of all those 
to which mankind are liable. What is under our imme- 
diate view is often assumed to be a fair representation 
of the whole, when it is the very reverse. 

This habit also produces the error of attaching an un- 
due value to the least important parts of a complex sub- 
ject, while we overlook or undervalue the most import- 
ant, and fail to discover the true relations of the various 
parts, so that the shadow is mistaken for the substance, 
and a most inaccurate and false estimate is formed of the 
whole subject. Moreover it leads to the great evil of 
learning important truths, without ever perceiving their 
practical applications. 

4. The habit of •properly sifting evidence or arguments, 
and adopting no opinion as a cognition loithout con- 
clusive proof , is requisite, on the one hand, to prevent us 
from accepting a proposition as true till we know that it 
is so, however much we may be prepossessed in its fa- 
vor, and, on the other hand, from rejecting the proofs of- 
fered in its favor, without due examination, however dis- 
agreeable it may be to our wishes. This habit will pre- 
vent us from stopping short till we have ascertained the 
foundations and character of the subject, which may be 
very different from what some allege or believe. It is in- 
dispensable to the attainment of real knowledge, and the 
avoiding of error. 

This habit is opposed to that of jumping at conclu- 
sions, before we have ascertained the real nature of the 
2iroofs by which they are supported, and assuming prop- 
ositions as true without any good grounds. This leads 
us to adopt the erroneous opinions of others, or the die- 



Sec. 2.] Habits. 125 

tates of our own wishes, as established truths. It is very 
easy to assume that to be true which we strongly desire 
to be so, or which is believed by those around us, while 
it is frequently a difficult and laborious task to ascertain 
where truth really lies. 

5. There are so many things to draw away our atten- 
tion from the pursuit of knowledge, and to retard and 
mislead us in our course, that, unless we acquire the hab- 
it of working actively and per sever ingly, amid difficulties, 
discouragements and disappointments, we may rest as- 
sured we shall not be successful. It is frequently much 
more agreeable, either to spend our spare time in pas- 
times and amusements, or to seek after knowledge in an 
indolent and slothful manner, than to apply ourselves act- 
ively and perseveringly to its attainment. Hence many 
have acquired the habit of either using no active exer- 
tion in acquiring knowledge, but taking everything on 
trust, that does not offend their prejudices, and rejecting 
everything that does, or of giving up the pursuit as soon 
as they get into difficulties, which they speedily do, as a 
matter of course : and hence much that has passed for 
knowledge, is little more than a web of errors and mis- 
conceptions. 

It has frequently been supposed that persons of com- 
mon abilities need not give themselves any great trouble 
about the acquisition of truth : for, if men of great tal- 
ents failed, could they hope to succeed ? Undoubtedly 
they could. If, as has often happened, men of great tal- 
ents are the slaves of various bad habits, they will fail in 
acquiring truth, when persons of much smaller abilities 
will succeed, provided they avoid such habits, and make 
the most of the powers which they possess. Difficulties 
are encountered even by the most gifted, who are gener- 
ally obliged to toil long and arduously, in order to ef- 
fect great results. If we do our best to acquire knowl- 
edge, we shall never be disappointed : for although it is 
a law of nature that great good is never secured without 
great labor, it is equally a law of nature that persevering 
care and diligence will overcome every obstacle to the at- 
tainment of the most important knowledge. 

It requires neither uncommon abilities nor wealth, in 
order to master the most important truths within the 
circle of human attainments. Bad habits are a much 
greater bar to progress than want of abilities or money ; 



126 Investigation in General. [Chap. VII. 

and, of these, habits of indolence and indifference are by 
no means the least powerful. Gold may purchase mate- 
rial wealth: but it neither secures truth nor excludes 
error. These objects require persevering and careful 
toil from the rich as well as from the poor ; and experi- 
ence has shown that the disadvantages of the former are 
greater than those of the latter. 

6. Not the least important of good habits is, that of 
investigating candidly, without yielding to the influence 
of prejudices, which are among the most fertile of all the 
sources of ignorance and error. They frequently pre- 
vent investigation altogether, and still more frequently 
render it abortive, by leading to the adoption of errone- 
ous opinions. 

This habit is opposed to that of allowing our wishes to 
turn away the attention from certain parts of the subject, 
and to view the rest hurriedly and negligently, a course 
which inevitably leads to error. Our wishes do not, in 
the least, change the nature of truth and falsehood ; and, 
in order to discriminate these from each other, we must 
view a subject as it is, and receive or reject proofs ac- 
cording to their real character. We must receive as true 
what is sustained by conclusive proof, however unac- 
ceptable, and reject whatever is destitute of such proof, 
however agreeable. 

7. Habits of temperance and self-control, or resisting 
the solicitations of desires and a]3petites which ought not 
to be gratified, are essential to the successful pursuit of 
truth. Dissipated and luxurious habits form an insur- 
mountable obstacle to great progress in the attainment 
of knowledge, while they tend strongly to root out all 
good habits, and introduce, in their place, those which 
are incompatible even with the retention, and much more 
with the acquisition, of knowledge. The investigator of 
important subjects must, in order to be successful, not 
only abstain from such things as are pernicious in any 
degree, but also guard against going beyond the bounds 
of moderation in what is proper 'and allowable. It is not 
enough to avoid the extreme of a debauch : he ought to 
shun the excesses of gluttony, exciting and frivolous pas- 
times, and the intoxicating paroxysms and reactive pros- 
trations of ungoverned passions. 

We are incessantly tempted to forsake the pursuit of 
knowledge altogether, or to investigate hurriedly, and 



Sec. 3.] Habits. 127 

without due care and attention, for the sake of present 
gratification, or escaping from present pain or uneasi- 
ness : and, unless we resolutely refrain from indulging 
such desires, the successful pursuit of truth becomes 
hopeless. 

This habit is not only of great importance in itself, but 
it is indispensable to the existence of other good habits, 
which will be speedily undermined, if we habitually yield 
to the desires of the present moment. The attention will 
be distracted ; the subject will be investigated carelessly 
and unmethodically ; we shall be misled by prejudices; 
our inquiries will be conducted without vigor or perse- 
verance ; and consequently error will usurp the place of 
truth. 

Those habits are opposed to that of self-indulgence, 
and sacrificing important future good for the sake of 
a fleeting present gratification, or exemption from tran- 
sient pain or toil, which is the most fertile of* all the 
sources of error, and the great barrier to the removal of 
ignorance. Its votaries dislike study, because it is less 
pleasant to their dark minds and groveling tastes than 
gross enjoyments or frivolous amusements ; and when 
the consideration of an important subject is forced on 
their attention, they gladly avail themselves of any falla- 
cy that first presents itself, to quiet their consciences for 
not examining it aright. They generally adopt those 
opinions which are most agreeable to their prejudices, 
without ever carefully examining whether they are true 
or false ; and if by chance they come to see that any of 
these is untenable, they usually supply its place with 
some similar error. 

In order to form good habits, we must obtain the dis- 
position proper for successful investigation, then consider 
the subject till we understand the nature and operation 
of those habits, and finally practice them, and shun the 
contrary habits. When once fairly adopted, this course 
becomes easy, as good habits are much more pleasant, in 
the long run, than bad, and that which has become ha- 
bitual is easily done, from the fact that it is habitual. 

§ 3. Of Things which require no Proof. — Why Intuitions require 
no Proof, nor Apprehensions. — Beality of Conceptions and Simili- 
tudes. — General expression of what needs no Proof. — Truths which 
admit of no logical Proof. — Sole pre-requisites to their admission. 

As the proof of a proposition is, that which shows that 



128 Investigation rsr Gekteeal. [Chap. VII. 

it is true, either absolutely or conditionally, intuitions re- 
quire no proof, because they are self-evident ; and there- 
fore no proof could add to their certainty, while -we could 
attempt to prove them only by assuming something tan- 
tamount to themselves. 

"With respect to apprehensions, we have already seen 
that they are matters of immediate consciousness, the 
reality of which admits of no rational doubt ; and proof 
is as superfluous as in the case of intuitions. 

Ideas are equally known by immediate discernment. 
When the idea of a well known person or place, for ex- 
ample, is present to the mind, we know certainly that 
-we discern such an idea, and that, if we did not, it could 
not exist, although its origin, or whether it ever had a 
prototype, is another question. 

A similar remark applies to conceptions. "When we 
form a conception of a whale or a sphinx, for example, 
we krtbw that we actually discern the phenomenon. 
Whether the likeness is correct, or whether such an ani- 
mal really exists, are questions which do not in the least 
affect the reality of the conception. 

All our comprehensions, including apprehensions, con- 
ceptions, and similitudes, are equally and certainly real ; 
for unless they were so, they evidently could not exist. 
They are all precisely what they appear to be, without 
any possibility of error, which affects only the inferences. 

Hence it appears that truths of Intuition and Compre- 
hension require no proof, which may be more briefly ex- 
pressed thus : discernments require no proof . 

Moreover all attempts to establish these truths are 
necessarily fallacious, since they must assume the very 
propositions which are intended or professed to be 
proved. Thus we cannot proceed a step to prove the 
reliability of Consciousness without assuming this as true, 
and all our processes necessarily involve that assump- 
tion.^) _ 

Before admitting a proposition as a discernment, all 
we require to know is, that it really belongs to this class 
of truths. We are indeed liable to take for self-evident 
even things which are self-evidently impossible ; and we 
sometimes assume fallacious inferences to be immediate 
comprehensions. Yet all that is necessary to distinguish 
comprehensions from all other propositions, is, an attent- 
ive and close consideration. That which is really self- 



Sec. 4.] Things admissible. 129 

evident, will clearly appear to be such when well under- 
stood and carefully considered; and the same process 
will readily distinguish comprehensions from inferences. 

§ 4. Of Things which mat generally be admitted as proved. 
— How mediate Knowledge is established. — Twofold division of 
Proofs. — Evidence. — Signs. — Testimony. — Deduction. — Primary 
foundations of sound Eeasoning. — Why frequently unnecessary to 
trace reasoning to these. — Mode of proceeding regarding External 
Objects. — (1) Principle regarding the causes of Apprehensions. — 
Chief source of Error. — How avoided. — Indications of Disease. — 
Circumstances in which the organs are liable to mislead. — Imita- 
tions of Nature. — Eeal source of many Mistakes attributed to the 
Senses. — General nature of Apprehensional Errors. — (2) Principle 
regarding Eemembrance. — Chief source of Errors attributed to 
Memory. — How they may be avoided. — (3) Principle regarding 
Testimony. — Origin of Ealsehoods. — When we may assume testi- 
mony to be correct. — What things require formal proof. 

As all knowledge is either mediate or immediate, that 
which does not belong to the latter must fall under the 
former ; and cognitions of that class are established by 
ascertaining that they are necessarily connected with 
our immediate knowledge, that which shows this con- 
nection being termed the proof. 

All proof is either evidence or deduction, or a combi- 
nation of both. 

Evidence is, any contingent fact which goes to estab- 
lish the proposition in question. It consists of signs and 
testimony. 

A sign is, something observed or comprehended by 
ourselves, which proves the thing in question by being 
its uniform antecedent, concomitant, or consequent, or 
by being directly and manifestly incompatible with its 
falsity. Signs are either internal, consisting of the phe- 
nomena of Memory and other internal comprehensions, or 
external, which consist of indications discernible by Ap- 
prehension. These comprise every apprehension which 
is known, either by experience or Intuition, to imply di- 
rectly the past, present or future existence of something 
different from itselfj so that most of our apprehensions 
belong to this class, and many of them are signs of vari- 
ous things. A sign indicates the past, the present, or the 
future, according as it is a consequent, concomitant or 
antecedent of the thing signified or indicated. 

Testimony is, a statement made by another regarding 
what he professes to have comprehended or to think. It 
F2 



130 Investigation in General. [Chap. VII. 

may either state the very thing in question from the wit- 
ness's own knowledge or some sign of it which he pro- 
fesses to have comprehended, or it may only declare 
what he has heard from other witnesses. 

Deduction consists of reasoning, which professes to 
show that the proposition in question is necessarily im- 
plied in something which either requires no proof or is 
already known, by some means, to be true, or is merely 
assumed to be so ; and it is tested by the criterions of 
reasoning formerly mentioned. 

If sound reasoning be traced to its foundations, we 
shall always arrive at intuitions, comprehensions or sup- 
positions, as the primary premises, because these are the 
only possible sources of mediate knowledge. But such 
a thorough investigation is generally unnecessary :. for 
when certain connections have once been established, 
they may be taken as proved, in all subsequent inquiries. 
We assume what has been already proved, and proceed 
thence, as a new starting point. 

When we have once clearly ascertained the connec- 
tion between certain apprehensions and their external 
causes, we generalize precisely as in other cases, and 
thenceforth assume that the same phenomena have the 
same or similar causes. So, when we have once ascer- 
tained that the phenomena of Memory must represent 
real prototypes, we assume this for the future. When 
we see certain complements of colors, and hear certain 
sounds, for example, we assume that these are caused by 
such and such substances, without or beyond ourselves : 
and when certain groups of ideas spontaneously arise, 
we assume that we apprehended their originals, without 
waiting to discuss the various possible sources of those 
ideas. 

We shall now mention the cases in which such assump- 
tions may be safely made, and the errors against which 
we have to guard, supposing the requisite degree of at- 
tention has been bestowed upon the immediate compre- 
hensions. 

1. Apprehensions may be assumed to be caused by 
agencies similar to those which were found to have caused 
such phenomena formerly . If, for instance, we see those 
colors and hear those precise tones, which we formerly 
apprehended, as Remembrance shows, when a certain 
friend addressed us, we may assume that the same friend 



Sec. 4.] Things admissible. 131 

is now present and addressing us. Here the principal 
source of error is, assuming that the same phenomena 
must have resulted from agencies precisely similar, if not 
the same, whereas these may be, in some respects, differ- 
ent. We are apt to attribute a phenomenon to the very 
same agencies which produced similar phenomena in our 
previous experience, overlooking the possibility of their 
being caused, in some cases, by agencies in several re- 
spects different. 

To guard against this error, we must ascertain that a 
phenomenon can be rationally attributed only to one 
cause or set of agencies. Such is the uniformity of na- 
ture, that deceptions of this kind form only rare excep- 
tions to a general rule. The principal sources of illusion 
are, a diseased state of the apprehending organs, and in- 
tentional imitations, Avhich exhibit phenomena that are 
usually caused by a different combination of circum- 
stances. When our organs are healthy, the various be- 
ings that surround us affect them with great uniformity. 
Thus we readily distinguish the countenance of one friend 
from that of another ; and we are in no danger of mis- 
taking the smell of a rose for that of an apple, although 
both belong to the class of fragrant odors. 

Disease of our organs is generally indicated by com- 
prehensible signs ; and it is only when the morbid affec- 
tion is violent or extensive that we are apt to be misled 
at all, while, in such cases, the indications of disease are 
generally palpable. Thus, a slight inflammation of the 
eyes does not prevent us from accurately distinguishing 
colors, and ordinary affections of the ear only increase or 
diminish its usual degree of sensibility. When disease 
has been violent and long continued, all mistakes are ob- 
viated by the organ's ceasing to perform its functions. 
The blind make no mistakes regarding colors, nor the 
totally deaf, regarding sounds. It is, therefore, only in 
particular cases of disease that mistakes are liable to be 
committed ; and, in these cases, we are put on our guard 
by palpable indications of the affection. 

With respect to imitations of nature, we generally 
know in what circumstances they are to be expected, 
and they are seldom so complete as to escape detection, 
on a close inspection. A juggler uses sleight of hand ; 
but this is out of the question in our ordinary intercourse 
with friends. So, a distant figure, seen at the end of a 



132 Investigation in General. [Chap. VII. 

long passage, may possibly be a statue ; but if we notice 
a similar appearance in a lonely uninhabited place, we 
justly infer that it is a real person. Again, a skilfully 
executed painting may be mistaken for its original, espe- 
cially when seen from a distance or in an obscure light ; 
but, on a close inspection, the resemblance is hardly ever 
complete ; and even when viewed from some distance, 
its unchanging appearance, as it is surveyed from vari- 
ous points, distinguishes it from a solid object. A ven- 
triloquist may imitate the pitch of the voice, to some ex- 
tent, so as to deceive us regarding the distance ; but as 
he cannot affect the directions in which the undulations 
strike the ear, without turning his voice into a mere echo, 
the origin of his utterances may always be detected. 

Intentional imitations must proceed from some mo- 
tive ; and as they generally require time and skill, they 
are seldom attempted, without some motive stronger 
than a momentary whim. An extensive acquaintance 
with the laws of nature, both mental and physical, would 
obviate every mistake of any consequence, likely to arise 
from this source. 

Many of the mistakes which are attributed to illusions 
of the senses, arise solely from inattentive observation, 
without apprehension being in the least at fault. Thus, 
we sometimes mistake one person's voice or countenance 
for another's, which it resembles, although a little close 
observation would show that there are peculiarities by 
which they can be easily distinguished. 

2. TJie clear presentations of Memory may be assumed 
to represent real originals, and prove our personal iden- 
tity. The processes by which Ave ascertain the connection 
between ideas and their prototypes, incidentally proves 
our personal identity, so far back as Memory extends. 
For it consists in continuity and similarity of thoughts, 
the corporal changes which incessantly occur having no 
influence on it ; and it would be as little affected by sim- 
ilar mental changes, even if they existed, which they 
probably do not. Our identity, and the reliability of 
Memory, having been once ascertained, they are after- 
wards rightly assumed, without any formal repetition of 
the processes by which they were first discovered. 

The principal sources of error connected with Remem- 
brance are the following, (l) Overlooking the peculiar- 
ities which distinguish ideas from phantasms, whence 



Sec. 4.] Things admissible. 133 

they are confounded, and we suppose that we apprehend- 
ed what we only conceived, (2) Overlooking the pecu- 
liarities which distinguish one similitude or apprehension 
from another. As the power of Memory is much strong- 
er than that of Conception, mistakes of the former sort 
are very rare. They occur chiefly where a lively con- 
ception is formed of a particular thing, and its phantasm 
is frequently considered, while the ideas of the things ap- 
prehended when it was formed are forgotten. Mistakes 
of the second kind are very common. We often mistake 
one thing for another, for instance, because we overlook 
the peculiarities which distinguish them, and which close 
observation would readily detect. 

In all cases where errors are attributed to Memory, it 
will be found that they are, in reality, attributed to un- 
sound reasoning, or to hasty and inaccurate observation. 
When a thing is quite forgotten, Memory cannot mislead 
us regarding it, any more than if we had never known 
it; and when the idea is faint, or unaccompanied by 
those of the other things apprehended at the same time, 
yet it is real, and its character suggests caution in draw- 
ing inferences. 

In our own case, a very moderate degree of attention 
will show us to which class a certain similitude belongs. 
If it be clear, and accompanied by equally clear simili- 
tudes of the other things comprehended simultaneously, 
we justly infer that all were so comprehended. When 
the case is otherwise, we should suspend a judgment till 
we can obtain some extraneous aid, such as that of notes 
or memorandums made by ourselves, or some evidence 
proceeding from others. By this means we may avoid 
errors proceeding from our own Memory. 

In the case of other persons, the only difference is, 
that they may misrepresent the actual nature of their 
similitudes. This point may possibly be determined 
from cross-questioning, from their general character, from 
the special relations which their views and interests bear 
to the testimony, from comparing their statements with 
those of other persons, or from facts ascertained by any 
other means. 

3. Things testified by credible witnesses may be as- 
sumed as true, so far as their actual experience extends. 
To invent a falsehood requires an effort, as it never arises 
spontaneously, the similitudes of things actually compre- 



134 Investigation in General. [Chap. VII. 

hended being always presented, except where the Will 
interferes with this result ; and the utterance of false- 
hood is always followed by thoughts more or less pain- 
ful, even where it escapes detection. Hence no person 
will relate a falsehood, without some particular motive ; 
otherwise it would be an effect without any adequate 
cause : and, therefore, where there is either no motive or 
none that could operate, there will be no wilful false- 
hood. Erroneous statements must arise, either from the 
relator's unwillingness or his inability to state what he 
knows to be true, or from his having been misled ; and 
hence, when there is no room to doubt the veracity or 
the ability, memory and opportunities of a witness, we 
may safely assume that his testimony is correct, as to 
what he actually comprehended. The inferences deduc- 
ible from that, is quite another matter. 

A proposition which does not belong to any of the 
classes now considered, requires formal proof. If it is 
neither a matter of immediate consciousness, nor one of 
the simple and ordinary inferences from the phenomena 
of Apprehension or Memory, nor related on the testi- 
mony of a credible witness, it has no title to be classed 
with cognitions, till it has been brought within the bounds 
of one or other of these classes, or of hypothetical truths. 

§ 5. General Modes of determining the Validity op Proofs. — 
Direct and Indirect Proofs. — Characteristics of each. — (1) Means 
of testing Signs. — When conclusive. — (2) First requisite regarding 
Testimony. — Frequent error and difficulty. — What must be ascer- 
tained. — Second requisite. — (3) Requisite in the case of Deduc- 
tions. — Hypothetical cases. — Reasoning from Probabilities. — Req- 
uisite in case of Absolute Conclusions. — Frequent Error. — (4) Ar- 
guments. — Proper course in cases of inadmissible premises, and of 
modifying or distorting the truth. — Primary premises requisite in 
investigations regarding Substances. — Certain Sciences not inde- 
pendent of experience. — Cases where the investigation of an argu- 
ment is needless. — Caution. — New premises. — Temporary cessa- 
tion of Attention. — General and partial Abstracts. — Testing final 
Conclusions. — Things to be constantly guarded against. 

Proof is either direct or indirect The former estab- 
lishes the proposition in question by direct means, and 
the latter, by showing that it cannot be false, or by es- 
tablishing something inconsistent with any other suppo- 
sition. Thus, when it is shown that a man is guilty of a 
crime, by the testimony of a witness who saw him com- 
mit it, the proof is direct ; and when it is proved that 



Sec. 5.] General Principles. 135 

another is innocent, by showing that he was at a great 
distance when the crime was perpetrated, the proof is in- 
direct. Both kinds of proof are often combined in an 
argument, the one corroborating the other. Thus, it 
may be argued that a proof is worthless, by demonstra- 
ting its inconclusiveness from direct analysis, and then by 
showing that it equally proves something which is oth- 
erwise known to be untrue. 

Either kind of proof is conclusive, when it conforms to 
the proper criterions : but the direct is usually prefera- 
ble, because it is more concise, more easily tested and 
less liable to error. In some instances, however, indirect 
proof is more satisfactory, because it is less easily forged, 
and more liable to detection when it is so concocted. 

1. In determining the character of signs, we must as- 
certain whether they are not compatible with the falsity 
of the proposition which they are supposed to prove : for 
they frequently establish only a slight probability. Thus, 
certain symptoms are often assumed as proofs that a per- 
son is affected with a particular disease, when in fact 
these symptoms accompany several other diseases. It is 
only where the signs are clear and unequivocal, that they 
are entitled to be received as conclusive proofs. If the 
mercury stands unusually high in the barometer, it is a 
sure sign that the atmospheric pressure is unusually 
great : but if we assume this proves it will be fair weath- 
er, we go farther than the sign warrants. Those cases 
where a phenomenon can be shown to prove a conclusion 
only by means of a chain of reasoning, come under the 
head of deduction. 

2. In cases of testimony, we should first ascertain 
whether it is conclusive, even admitting it to be true : 
for it is often assumed to prove a proposition when it 
only proves something like it, and essentially different. 
In many instances, it is rendered suspicious by our ina- 
bility to determine whether the statement is not a doubt- 
ful inference from what was actually apprehended, as 
when a man says he was cured of a certain disease by 
using such a medicine, when, in fact, it is doubtful wheth- 
er he ever had the disease, and still more doubtful wheth- 
er the medicine had any beneficial effect. Unless we 
know the phenomena actually comprehended, the testi- 
mony is always inconclusive, except in those cases where 
there is no ground to suspect erroneous inferences. 



136 INVESTIGATION IN GENEBAL. [ChAP. VII. 

If we find that the testimony conclusively proves" the 
point in question, supposing it to be true, we must next 
determine whether it actually is so ; and, in order to this, 
we must ascertain whether it possesses all the requisites 
of reliable testimony. If it does, it proves the point in 
question : otherwise it does not. 

3. In order to render deductions satisfactory, it must 
be ascertained that they possess the four characteristics 
of valid reasoning, formerly stated. 

In hypothetical cases, the primary premises are some- 
times mere suppositions ; and the only thing to be ascer- 
tained regarding them is, whether they are expressed so 
clearly and precisely that there is no danger of mistaking 
one for another. If not, they are inadmissible : for it 
would be impossible to determine whether the subse- 
quent reasoning were valid, since we could not ascertain 
to which of several things it applied. 

Sometimes the primary premises are only probabilities ; 
and the conclusion consequently partakes of the charac- 
ter of its bases. We reason from the premises as if they 
were cognitions, and then attribute to the conclusions 
the same degree of probability which, we believe, per- 
tains to its foundations. "We should mark the degree of 
probability belonging to the premises, and limit the con- 
clusion accordingly. The reasoning, in other respects, is 
tested precisely as in cases where the primary premises 
are certain. 

In all cases where the conclusions require to be proved 
absolutely, and not merely hypothetically, or as proba- 
bilities, the primary premises, besides being clear and 
precise, must also be true. This is to be ascertained by 
observing whether they belong to that class of proposi- 
tions which need not be proved, or whether satisfactory 
proof has been already obtained, either by conclusive test- 
imony, or by deducing them from the former class of 
truths. If the premises are objectionable in this respect, 
they are inadmissible, since otherwise we should assume 
as true what is possibly false, and thus build on an un- 
stable foundation. 

It frequently happens that the premises are true in 
one respect, but not in the sense in which they are as- 
sumed. It is true, in one sense, for instance, that " hu- 
man testimony is fallacious," meaning " some human tes- 
timony :" but it is very false in the sense that " no hu- 



Sec. 5.] Genekal Principles. 137 

man testimony is conclusive," which is the sense some- 
times attributed to it. This kind of error is greatly fos- 
tered by the use of metaphorical or figurative language : 
for as it is often ambiguous, it admits of different inter- 
pretations ; and those who employ it have frequently no 
clear conception of what they mean, and slide uncon- 
sciously from one signification to another. 

4. In arguments, various assumptions are generally 
made, and different conclusions are deduced from them, 
in the first instance, but all going to establish the final 
conclusion. Some of these premises may be admissible, 
and others not. If any of the latter be an essential part 
of the argument, this vitiates the whole : but, in some 
cases, the undue assumption is immaterial. To which of 
these classes a premise belongs, can frequently be determ- 
ined only after some progress has been made in the ex- 
amination of the subject. Here we ought to proceed 
until we can ascertain whether the undue assumption is 
material, in which case the whole argument is worthless, 
or whether it be not immaterial, in which case we must 
beware of rejecting the whole argument as worthless, 
which would be like inferring that the main channel of 
a great river must be dry, because we have found some 
of its tributary rivulets dried up. 

Sometimes the assumptions are partially correct, and 
only exaggerations or modifications of the truth. Here 
we adopt the same course as in the preceding case, and 
observe whether the subsequent reasoning is supported 
by the real facts, when stript of the distortions to which 
they have been subjected. If not, the argument is futile. 

In all legitimate investigations regarding substances, 
the primary premises must consist, at least in part, of 
comprehensions or inferences from them : for intuitions 
alone teach us nothing regarding the existence of such 
things, and hypotheses here serve only to aid us in de- 
ducing necessary consequences. Hence all attempts to 
construct physical or mental sciences, independently of 
experience, must necessarily fail : for the reasoning will 
either be inconclusive, or occupied with puerilities and 
questions beyond the reach of human investigation. 

In some cases, the argument is known to be invalid 
from the conclusion being either self-evidently false or 
quite incompatible with some known truth. Wherever 
this is, in reality, the case, it is unnecessary to test the 



138 Investigation in General. [Chap. VII. 

argument, as it must be fallacious. But we should be 
cautious in making such admissions, since incompatibili- 
ties of this kind are sometimes alleged or supposed, 
where they do not exist, the proposition said to be in- 
compatible being either false or not, in reality, inconsist- 
ent with the one in question. 

Wherever new premises are assumed, in the course of 
an argument, we should test their character like that of 
the first assumptions. 

The attention should be closely fixed on the subject, 
while we are examining an argument : for if this flags 
only for a little time, we may then encounter and fail to 
detect, a faUacy which vitiates the whole. This is par- 
ticularly apt to happen in examining long arguments; 
and it is a good rule, in such cases, to stop whenever our 
attention cannot be prevented from wandering except by 
a strong effort of the Will, and not resume the investi- 
gation till we are able to do so with unflagging attention. 

In difficult cases, much aid may be derived from writ- 
ing an abstract of the whole argument, omitting all de- 
tails of facts, and inserting only the essential parts, which 
never occupy a large space, even in the longest argu- 
ments. This will enable us to take a general view of the 
argument, and attend particularly to the more important 
parts. We are apt to think that we thoroughly under- 
stand an argument, merely from reading or hearing it, 
while reducing the substance of it to writing may show 
us that we do not rightly understand even its essential 
parts. 

Where the difficulty lies in a particular part of an ar- 
gument, this alone may be written as fully as its nature 
requires. Millions have been misled by fallacies which 
cannot fail to be readily detected by any person who 
simply writes them down and attentively considers them. 
But, in doing this, we should attend to every essential 
part : for the strength of a fallacy frequently lies in its 
assuming something as true which is never expressed, 
and which a careful consideration will show to be false. 

If we find that a conclusion is logically established, we 
should then ascertain whether this is the proposition in 
question. In order to this, we must compare the one 
with the other, and ascertain whether they are virtually, 
if not completely, identical. If so, the argument is sound : 
otherwise it is worthless, because it is beside the subject. 



Sec. 1.] Nature and Uses oe Study. 139 

Throughout every investigation of proof, we must be- 
ware of being misled by vague or indistinct thoughts, or 
by obscure, ambiguous, or unknown expressions, both of 
which are frequent sources of fallacy. 



CHAPTER VIII. 

OF STUDY. 

§ 1. Nature and Uses op Study. — Knowledge Original and Sec- 
ondary. — The latter acquired by Study. — Why first considered. — 
Its Importance. — General objects of Study. — Various other ad- 
vantages. 

Knowledge is either original or secondary. The for- 
mer consists of that which is acquired without any direct 
assistance from others, or in addition to the previous at- 
tainments of mankind, by means of what is termed orig- 
inal investigation : the latter consists of that which has 
been previously acquired by others, and is communicated 
to us by means of some known signs, the investigation 
of which, for the purpose of learning what they profess 
to convey, is termed study. This claims our first atten- 
tion, because it is of easier acquisition, and we are sel- 
dom in a proper position to enter upon original investi- 
gations of much consequence, until we know what others 
have already accomplished. It is only after this has been 
acquired, that any person can reasonably hope to make 
important additions to the stock of human attainments. 

The knowledge acquired by study is by far the most 
important of our attainments, subsequent to those of 
early childhood, since the original acquisitions, even of 
the most gifted and favorably circumstanced, form but 
a very small fraction of the whole body of human knowl- 
edge. This holds true of necessary, as well as of contin- 
gent, truth, as to the latter of which we cannot evidently 
go beyond the bounds of our personal experience with- 
out the aid of others ; and although we might, by possi- 
bility, learn much of the former by our own unaided ef- 
forts, yet, considering the great labor and difficulty of 
establishing many of the conclusions, we cannot expect 
to master much of the subject without extraneous aid. 

The general objects of study are, to discipline the fac- 
ulties, form proper habits of investigation, and communi- 



140 Study. [Chap. VIII. 

cate to the learner the previous attainments of mankind. 
But it frequently effects several other purposes. Obscu- 
rities and ambiguities are removed ; fallacies are detect- 
ed ; that which was locked up in an unknown language 
is set forth in the vernacular ; the fragments of knowl- 
edge formerly disconnected and hidden from the view 
even of intelligent men, are collected and made to illus- 
trate each other, so that we obtain a more extensive and 
accurate knowledge of the subject than was hitherto pos- 
sessed by any, and thus we see various parts of it in a 
new light, and ascertain what is defective or redundant. 
By these means, study not only renders previous attain- 
ments available, but it also prepares the way for new dis- 
coveries and inventions, so that it frequently leads to suc- 
cess in original investigations. 

§ 2. Subjects, Modes and General Rules op Study. — Selection 
of Subjects. — Order of Study. — Proper course regarding certain 
Subjects. — Advantages of previously considering the Objects of 
Study. — Preliminary Studies. — Extent of Study. — Three modes of 
Study. — Advantages of Written Communications, of Conversation, 
and of Lectures. — Disadvantages of the last. — Proper course, on 
controverted Subjects. — Rules regarding Prejudices. — Meaning of 
Terms. — Evils of disregarding them. — Requisite in order to be in- 
structed by Language, and understanding it aright. — Advantage 
of a good knowledge of the Language. — Mode of dealing with Dif- 
ficulties. — Evil of deviations, and of cramming. — Proper course. 
— Common mistake of beginners. — General Rule for surmounting 
Difficulties. — Advantages of careful and thorough Study, and evils 
of the opposite course. — Testing Statements. — Requisites before 
receiving an Argument as Sound. — When another instructor should 
be sought. — Sources of information which should be used. — What 
subjects should be studied simultaneously. — Recreation. — Laws of 
Health. — Einal reviewing. 

In selecting subjects for study, we should first attend 
to those which ought, on account of their general import- 
ance, to be understood by all, whatever be our peculiar 
pursuits or tastes, and then to those that relate to our 
particular vocation. Both of these are frequently stud- 
ied, to some extent, under teachers, in early life. But 
this by no means dispenses with independent study, in 
order to render our knowledge of them accurate and 
extensive. We may afterwards attend to those studies 
and investigations to which we are led by our individual 
tastes and circumstances. These ought not to be taken 
up sooner, lest the former should not receive due atten- 
tion, and our attainments be most extensive on subjects 
of comparatively little importance. 



Sec. 2.] Subjects and Modes of Study. 141 

The only modification requisite, in investigating a 
branch already studied under a teacher, is, that we may 
hurry over those parts which we already sufficiently 
know or understand. But a little self-examination, after 
really mastering the subject, will frequently show us that 
these form a much smaller part of the whole than we had 
supposed, and that, while our views of some parts were 
confused and erroneous, we were totally ignorant of oth- 
ers. 

Before commencing the study of a subject, we should 
consider the objects which are to be accomplished by 
mastering it. If we cannot find any good object, we 
should give up all thoughts of studying it : for if we do, 
the only results will probably be, that we shall spend 
time to no purpose, and form a habit of studying in a 
careless manner, and roving from one subject to anoth- 
er, without acquiring more of any of them than a slight 
smattering, which only fosters a groundless conceit of 
varied knowledge. 

If, on the other hand, important objects will be secured 
by properly studying a subject, a view of them will in- 
crease our diligence and attention, and a review of them 
will revive these, when they begin to flag. We shall 
thus secure the greatest degree of attention to the most 
important subjects, while a contrary course is apt to pro- 
duce effects precisely the reverse, since that which is least 
important, frequently strikes the fancy of an ignorant per- 
son more readily and powerfully than the most weighty 
subject. 

A preliminary requisite, in many cases, is, a competent 
knowledge of those branches on which the one in ques- 
tion is based, and which it assumes and applies as al- 
ready known. Thus, we cannot master Dynamical As- 
tronomy without a knowledge of Dynamics ; nor can we 
acquire a knowledge of the latter till we have studied 
Mathematics. We should not enter upon a subject till 
we know that it will reward our labors, and we. have ob- 
tained a sufficient acquaintance with the other branches 
requisite to successful study: and when we have taken 
it up, we should not lay it aside till we have mastered as 
much of it as our circumstances permit or require. 

Communications from others may be writte?i or oral, 
and the latter may be colloquial or formal. 

Written communications possess the great advantages 



142 Study. [Chap. VIII. 

of enabling us to consider any part as often and as delib- 
erately as we please, to compare the various statements 
of different persons, to trace carefully every part of a 
chain of reasoning, and to make a correct abstract of the 
whole, a thing which ought to be done, in all cases of 
difficulty and importance. Another great advantage of 
writing is, that it enables us to test every statement, 
without any risk of mistaking it. This is frequently im- 
practicable in oral communications, on account of our in- 
ability to remember the very words employed. 

Conversation is more lively, and allows us to propose 
difficulties, to have ambiguities or obscurities removed 
directly, and to make inquiries which will give us a fuller 
and more correct view of the subject. This is on the 
supposition that the instructor understands it thorough- 
ly. If he does not, questioning will detect his deficien- 
cies more readily than formal lecturing, which possibly 
may only echo another's expressions, that were misun- 
derstood by the speaker. 

Public addresses enable a person to convey his thoughts 
to many simultaneously, while they unite, in some de- 
gree, the liveliness of conversation with the precision and 
regularity of written discourse. But they lack the means 
of careful examination and review supplied by the latter, 
and the advantages of questioning the instructor afford- 
ed by the former, so that it is impossible to master any 
science or any difficult subject by this means. One part 
is apt to withdraw our attention from another, which 
may be equally important, while the strong sympathetic 
emotions frequently produced by the presence of a mul- 
titude, tend in the same direction. Hence we wholly 
lose much of what is said ; some parts are forgotten, and 
others are misunderstood. Consequently lectures are 
better adapted to amuse, or rouse emotions, than to con- 
vey solid instruction. 

On controverted subjects, it is desirable to examine 
some of the best authorities on each side : for, in such 
cases, men are apt to conceal or misrepresent, so that we 
cannot obtain a correct view of the subject without ex- 
amining both sides. Even when we find, as frequently 
happens, that one party is right, in the main, and the oth- 
er as much in the wrong, an examination of the objec- 
tions and arguments of the latter will give us a clearer 
and more extensive view of the whole subject than we 



Sec. 2.] Genekal Rules. 143 

could obtain by studying the productions of one party 
exclusively. Truth always gains by a close and candid 
examination : for the more it is investigated, the more 
certain will it appear, while error appears more baseless 
and absurd, the more closely it is examined. Hence truth 
can never suffer from proper investigation, which gener- 
ally explodes error. 

We must constantly guard against the influence of 
prejudices, which tends to make us overlook several 
things altogether and to consider the rest without due 
care and attention. A little reflection will generally show 
us the nature of the bias against which we have to guard : 
and when the statements made agree with our wishes, 
we should be particularly cautious in receiving them as 
true, without the most conclusive proof. On the other 
hand, we must beware of rejecting as unproved a state- 
ment which conflicts with our prejudices. 

We are apt to take arguments which chime in with 
our cherished views or wishes as conclusive, when possi- 
bly they may be quite worthless, while we are equally 
disposed to reject, as fallacious, arguments which mili- 
tate against our desires. Hence we should never receive 
the former as satisfactory, till we have tested them most 
rigidly, while we should never reject the latter as incon- 
clusive, till we have proof that they are so, beyond the 
possibility of a rational doubt. We can generally ascer- 
tain whether we have done so, by submitting the proofs 
to intelligent persons whose prejudices run counter to 
our own, and fairly weighing their objections, or by com- 
paring them with the arguments of those who hold op- 
posite views of the subject. 

The precise significations of obscure, ambiguous or 
unknown terms should be ascertained as they occur ; for 
otherwise our labors will only fill our minds with mis- 
conception and error. We may have often heard or read 
many words and expressions of this class, without ever 
knowing their real signification ; and few things have 
tended more to produce and perpetuate error, than the 
free employment of such terms by writers, and their 
ready acceptance by readers, without any precise defini- 
tions of the senses in which they were employed or un- 
derstood. By this means we are liable to think that we 
understand a subject, when our actual knowledge of it 
is nearly confined to a string of unintelligible or vague 



144 Study. [Chap. VIII. 

phrases, to which "we do not attach any precise and ac- 
curate signification, and we have hardly ever looked be- 
yond the mere words. 

We should avoid the common error of assuming that 
a knowledge of names and definitions is tantamount to a 
knowledge of the things named or defined. In order to 
understand the exact import of terms relating to phe- 
nomena, we must first know, by our own experience, the 
nature of their primary elements, and then determine 
what combination of these is denoted by the particular 
term in question ; and we must always consider the thing 
signified, apart from its name : otherwise, we cannot 
rightly understand what it is, and our supposed knowl- 
edge of the subject will be little more than a compound 
of ignorance and. positive error. 

We cannot acquire real knowledge by means of terms 
whose import we do not know : and, therefore, although 
it frequently requires time and labor in order to ascer- 
tain the exact and proper meaning of words, it ought al- 
ways to be done ; else the study will probably mislead 
and injure, instead of enlightening and improving. In 
effecting this, it is often necessary to consider the things 
denoted, apart from language, and then compare them 
with the usages and formal definitions of those who best 
know and most accurately employ the terms by which 
they are expressed. 

The student should possess a good general knowledge 
of the language employed by the person whose expres- 
sions he is studying : otherwise he will be very apt to 
misunderstand them. He should not presume that he 
possesses a competent knowledge of the language, be- 
cause it is his vernacular, of which we learn only the 
smaller and easier part without the aid of regular study. 
We should, therefore, be properly prepared on this point, 
before commencing the study of any subject of import- 
ance, in order that we may know what is said, and its 
real import, which cannot be discovered till we first know 
precisely what it is. 

When the student meets with statements and reason- 
ings which he cannot readily understand, he should con- 
sider them deliberately, and compare one part with anoth- 
er. If he should not then see through them, the difficul- 
ty should be reduced to writing: for this concentrates 
the attention, so that it sometimes vanishes by the time 



Sec. 2.] General Rules. 145 

it is written down. If it still continue, reference may- 
be made to some other authority ; and if this does not 
suffice, it should be noted, and reconsidered at some fu- 
ture time. A more extensive acquaintance with the sub- 
ject, or a better frame of mind, may render it very in- 
telligible. Difficulties which resist our efforts to master 
them, in the course of formal study, frequently disappear 
when we casually think of them calmly, while we are not 
particularly engaged otherwise. The mental vision re- 
sembles the physical, in our sometimes seeing an object 
better by means of an indirect glance than by a direct 
gaze. 

The learner is always liable to be drawn away from 
his proper subject to collateral, but distinct, matters 
which it suggests ; and he must beware of being thus 
led wholly off his path, or spending so much time on de- 
vious questions as unduly to retard his progress towards 
his proper object. Otherwise he will be apt to run from 
one subject to another, and resemble a traveler who in- 
cessantly deviates to the right and left, so that he never 
reaches his journey's end. 

We should not study longer than we can do so with 
steady attention; and every part should be considered 
deliberately, without caring whether this requires more 
or less time. When a person hurries impatiently for- 
ward, anxious only to finish the subject as soon as possi- 
ble, and merely crams his Memory with what he reads 
or hears, without observing its character or bearings, or 
even comprehending it aright, he will generally accom- 
plish nothing of any value, and only acquire bad habits 
of study. What is apparently acquired, is partly misun- 
derstood and blended with erroneous views ; things 
widely different are confounded with each other ; and the 
little that is really mastered, will be soon forgotten, while 
the hurried and irksome process is apt to give the learn- 
er a dislike for the subject, and to unfit him for careful 
and thorough investigation. 

We should study the successive parts deliberately and 
attentively, ascertain the exact import of the expressions, 
master the ai'guments, observe the connection between 
one part and another, and ascertain their general bear- 
ings and relations. We shall thus avoid the habit of 
careless and inattentive study, and at the same time ob- 
tain a good understanding of the subject of our labors. 



146 Study. [Chap. VHL 

and remember permanently, at least its more important 
parts. 

When a subject is studied with the requisite degree 
of care and attention, the learner's progress is apt to be 
slow at first, especially in studying science ; and he is in- 
clined to think that it forms an endless task. But a bet- 
ter acquaintance with it will dispel this error ; and he 
will find that perseverance, care and diligence will ena- 
ble him to surmount, within a reasonable time, every dif- 
ficulty which he encounters. In order to this, however, 
he must begin by concentrating his attention on one 
short and simple point, and mastering it before proceed- 
ing to the next. The art of surmounting difficulties of 
study lies in this, attentively considering the simple ele- 
ments separately. However complex a subject may be, 
it always consists of very simple elements, just as the 
largest book is made up of a few letters, and the most 
complex machine consists of a few simple elementary 
structures. 

A careful and thorough method of study from the out- 
set, is the quickest, easiest and most pleasant means of 
acquiring a good knowledge of the particular subject, 
while it aids us in forming proper habits of investiga- 
tion, whereas a contrary course not only prevents us from 
ever acquiring a good knowledge of that subject, but 
also, by fostering habits of hasty and careless investiga- 
tion, tends to keep us ignorant on other subjects. It 
leads us to adopt the errors of others, and add many of 
our own. 

Those who skim along the surface, or run from one 
study to another, without rightly finishing any, can ac- 
quire a good knowledge of none of them, while the bad 
habits they form, become inveterate. In order to mas- 
ter the subject, train the intellect aright, and form prop- 
er habits, the student must proceed deliberately, and 
avoid hurry and superficial work. These lead to time 
being lost in acquiring narrow and erroneous views, 
which must be unlearned before he can acquire an accu- 
rate knowledge of the subject ; and this now becomes 
more disagreeable than at the first, because it has lost 
the charms of novelty. 

The statements and reasonings should be tested by 
the proper criterions, as they occur. Thus, when as- 
sumptions are made, on the authority of Consciousness, 



Sec. 2.] General Rules. 147 

we should observe whether they are really discernments ; 
where statements are made on testimony, we should try 
whether it is satisfactory ; where a conclusion is inferred 
from certain premises, or held to have been already le- 
gitimately established, we should examine whether this 
is actually the case ; and where a conclusion is logically 
proved, we should ascertain whether it is the real point 
in question, or the one which ought to have been proved. 

Our inability to detect a fallacy should never lead us 
to receive an argument as sound, unless every essential 
part is found, upon proper examination, to accord with 
the criterions of truth. "We are not warranted in assum- 
ing that it is sound, simply because we do not see that it 
is otherwise ; and the proper course is, to assume that 
everything is fallacious, for the truth or correctness of 
which we have not the evidence of Consciousness, at 
every step, and in every part : otherwise we shall fre- 
quently adopt gross error as demonstrated truth. For 
the most pernicious errors can be sustained by plausible 
arguments, which sound and look well, and whose real 
character cannot be detected without a close and atten- 
tive examination. Some attempt to avail themselves 
safely of others' labors, by simply adopting their conclu- 
sions, without any proper examination of their argu- 
ments : but this course is always liable to mislead ; and 
it has very frequently led to the adoption of the most 
pernicious errors. 

The best accessible sources of information should al- 
ways be used; and the student should never rest satis- 
fied with a doubtful authority, when he can consult one 
which is unquestionable. Thus, he should not take sec- 
ond-hand accounts of an author's doctrines, when he can 
consult his own writings ; a prevaricator should not be 
listened to, where a person of strict veracity testifies on 
the point ; and he should not pay any regard to hearsay 
or flying rumors, when he may obtain the statements of 
a credible eye-witness. So, he should not employ a teach- 
er who expresses himself vaguely, obscurely or unintelli- 
gibly, reasons fallaciously, or arranges his materials con- 
fusedly, when he may have recourse to another who is 
free from such defects, and in no important respect infe- 
rior. 

We should never study at a time more than one sub- 
ject requiring close and deep thinking, since otherwise 



148 Study. [Chap.VIH. 

we cannot devote the requisite degree of attention to 
each, because they have a tendency to draw the atten- 
tion to themselves, even when we are engaged with other 
matters. But such studies should be intermingled with 
those which entertain the mind, without seriously im- 
pairing its energies. 

Study should be diversified, at moderate intervals, with 
pursuits requiring active, but not toilsome muscular ex- 
ercise, and forming an agreeable relaxation for the mind : 
otherwise what is learned is apt to be mastered imper- 
fectly, and speedily forgotten. 

The student will be quickly incapacitated for success- 
ful efforts, unless he attends to the laws of health, and 
avoids deleterious agencies and practices : for disease not 
only injures the senses, and the power of accurate observ- 
ation or continued application, but it also distracts the 
attention and impairs the Memory, so that it generally 
renders successful study impracticable. 

Before finally discontinuing the study of a subject, the 
whole should be reviewed mentally, and reference made 
to a teacher or a book only when we are at a loss. The 
foundations, scope and connections of the various parts 
should be considered, until we clearly understand and re- 
member them. We should also ascertain what properly 
belongs to the subject, mark the parts of which our 
knowledge is defective, and rightly employ the best means 
within our reach for supplying the deficiency. Without 
some such course as this, it is generally impossible for 
most persons to possess a good and extensive knowledge 
of the subject, or to see the amount of their real attain- 
ments. We are often apt to think that we know a sub- 
ject well, when this process will show us the contrary, 
and convince us that our knowledge of it is much less 
extensive and accurate than we supposed. 

§ 3. Selection' axd Study of Books. — Great Importance of Writ- 
ings. — Xo privileged road to valuable Knowledge. — Means of dis- 
covering good and detecting bad Books. — Characteristics of the 
best works for Beginners. — Two evil Practices. 

In every study of any extent, we require the aid of 
written or printed materials, in order to understand the 
statements aright, and impress them on the Memory, and 
also to follow the chains of argument, and test their va- 
lidity. To be convinced of this, we need only consider 



Sec. 3.] Books. 149 

the extreme difficulty of remembering the substance of 
a discourse, after one hearing, or following an ordinary- 
mathematical demonstration, without the assistance of 
visible words and symbols. 

There is no privileged easy road to valuable knowledge 
of any kind. It is not enough to sit down and passively 
read or listen to the words of a teacher : we must act- 
ively attend to what is said, test it properly, and commit 
more or less of it to Memory. The best teacher can only 
assist the learner : the subject must be mastei'ed, and the 
chief difficulties surmounted, by his own individual ef- 
forts. Hence the necessity of having recourse to books, 
in order to obtain a correct knowledge of any subject. 

On most subjects of importance, numerous works have 
been published, of very different degrees of merit. Some 
are of such a character that time spent in studying them 
would be thrown away ; and even where several are 
good, one may be much better than any of the rest. 
Hence care should be taken to procure the best : and, for 
this purpose, the advice of judicious persons well ac- 
quainted with the subject and its literature, is of great 
service. But we must beware of regarding the opinion 
of a distinguished man, on a subject with which he is not 
well acquainted. A great chemist may be a bad guide 
in Mathematics ; and one well skilled in Elementary Ge- 
ometry may know very little of Mathematical Analysis. 

It is equally requisite to ascertain whether the person 
to whom we apply is not under the influence of strong 
personal, party or national prejudices, which may render 
his opinion unreliable. The opinions of anonymous and 
unknown critics cannot be safely followed, because they 
may really know little of the subject, or be influenced by 
strong prejudices or sinister motives. 

In the absence of any reliable advice from others, we 
may frequently detect a worthless book by certain char- 
acteristic marks. Sometimes the very title shows that 
the writer knows little of the subject, as where it prom- 
ises a refutation of the Copernican system of Astrono- 
my, or a disclosui'e of the means of living as long as we 
please, or of constructing machines that can be moved 
by weights without ever being wound up. Occasionally 
the author evidently commits a fatal error at the outset, 
such as assuming, in effect, the very thing he professes 
to prove, or attempting to prove something self-evidently 



150 Study. [Chap. VIII. 

impossible. In other instances, he expresses himself in 
such a manner that we cannot discover his meaning, on 
fundamental or material points. 

In many cases, the character of a book may be discov- 
ered by special tests. Thus, the impartiality of an histo- 
rian may be tried by observing how he handles a sub- 
ject with which we happen to be well acquainted, just 
as we test the accuracy of an Atlas, by looking at the 
representations of parts with which we are familiar. So, 
the reasoning powers and ingenuity of an author may be 
ascertained, by observing how he discusses some point 
of peculiar difficulty ; and, in the same way, we can often 
determine whether he is credulous or sceptical, indolent 
or industrious, learned or ignorant, modest or conceited, 
loose or precise in his statements, and so forth. 

On first beginning the study of a subject, we should, 
if possible, choose a work which avoids the dryness of 
brief outlines, on the one hand, and tedious details and 
discussions on the other. The former are generally un- 
interesting for their meagerness, and frequently substi- 
tute the shadow for the substance, while the latter weary 
a beginner by their prolixity. The best book for a be- 
ginner- is, one which goes systematically over the whole 
ground, and refers to no other source for rudimentary 
instruction, which is fair and accurate in its statements, 
sound in argument, clear and precise in style, and which 
exhibits the subject in its most improved form, without 
omitting anything of great importance which falls with- 
in its scope. 

Having selected a text-book, we should confine our at- 
tention to it, till we have perused and understood it, ex- 
cept where we meet with some difficulty which resists 
our best efforts to surmount it, or some defect which must 
be supplied from another source. Flying from one treat- 
ise to another distracts the attention, and is apt to pro- 
duce erroneous views of the subject. But, after proper- 
ly finishing one good general treatise, we may advan- 
tageously consult other works, which contain views or 
matter not found in the former. Our previous attain- 
ments will render it unnecessary to do more than run 
over these productions, and attend chiefly to what is new 
to us. 

We should avoid the pei'nicious custom of running 
from one part of a book to another, and not studying it 



Sec. 1.] General Character, &c. 151 

continuously from the beginning, which is the proper 
method. What precedes, is generally the foundation of 
what follows, especially in scientific works Hence we 
cannot rightly understand the subject, unless we peruse 
the book in regular order; and even the little that we 
do leai-n, is so disconnected that it is mostly forgotten, 
after a short interval. 



CHAPTER IX. 

OF ORIGINAL INVESTIGATION". 

§ 1. General Character, Uses, Prerequisites, and Methods op 
Original Investigation. — Why Original Investigation is more 
difficult than Study. — How it differs from Study. — Why its fields 
are gradually narrowing. — Advantages of original Researches and 
new Discoveries. — Superiority of personal Observations. — Why 
those of others should not be overlooked. — Relation of the preced- 
ing to the present subject. — Means of selecting subjects. — Seven 
Prerequisites, and remarks. — Two methods of proceeding. — Subdi- 
vision. — Six Rules regarding the course of proceeding. 

Original investigation presents greater difficulties 
than study, because it is more indefinite. While we 
consider only cognitions, we may easily know the pre- 
cise thing to be done : but when we enter on the region 
of the unknown, we are often at a loss which way to di- 
rect our course. In study, words and direct representa- 
tions guide us to the knowledge of the things in ques- 
tion : but here we should begin with the latter, and end 
with the former, which should not be employed till we 
know the precise thing which we denote by them ; and 
when that is done, we should write this down, wherever 
there is any danger of our afterwards forgetting or mis- 
taking it. 

While the fields of study are becoming more extensive, 
as time adds to the truths already known, those of orig- 
inal research are becoming gradually narrower, not only 
because less remains to be discovered, but because new 
additions to the stock of knowledge frequently render it 
more difficult to place ourselves on the vantage ground 
for making further additions. Yet mankind are far from 
having reached the boundaries of possible attainments ; 
and if new discoveries increase the preliminary labors of 
subsequent explorers, new inventions may aid them in a 



152 Oeigixai. Investigation. [Chap. IX. 

corresponding degree, while the "wider generalizations 
and more compact and regular arrangement of materials, 
resulting from increased knowledge, frequently facilitate 
future acquisitions more than this difficulty retards them. 
"When the materials are confusedly arranged, and con- 
sist of unconnected fragments, intermixed with many 
errors and redundancies, as is often the case in the earner 

gjes of a science, it may require more time to learn 
the little that is known, than it will take to master the 
whole, after original investigations have given it a more 
regular and connected form, and banished the crude 
speculations, positive errors, and prolix irrelevane:^ ;:' 
its rudimentary st _ as. 

Original researches or observations are evidently the 
only means of making additions to the sum of human 
knowledge, or discovering something that nobody knew 
before. They also detect errors, or confirm previous re- 
searches, even when they fail to make any such additions. 
Many instances occur, in the history of science, where 
things assumed tor ages, as established inductions, were 
found, by subsequent research, to be totally erroneous. 
Of this the old opinion regarding the influence of the 
Moon on the weather and vegetation, is a good in- 
stance. 

In other cases a proposition, true in the main, may be 
found to have been either too wide or too narrow, or to 
have involved some degree of positive error. It is also 
no small advantage that disputed points should be estab- 
lished, by an irresistible mass of evidence, beyond further 
cavil or contradiction, from any person who has proper- 
ly examined the subject, even although the mat:?, in 
question may have been virtually established before. 

Original observation also gives us, in many cases, a 
more lively impression and more exact knowledge of 
things, than we could obtain from descriptions, as Con- 
ception is more feeble than Apprehension, and at the 
same time more liable to mislead us, to say nothing of 
the numerous mistakes arising from language. But we 
should not forget, on the other hand, that a person well 
acquainted with the whole subject, may give us a more 
extensive and accurate knowledge of it than we could 
acquire by our own unaided observation. TTe should, 
therefore, never fail to examine the statements of other 
intelligent men who have examined the same objects. 



Sec. 1.] Prerequisites. 153 

They will generally furnish important aid towards a good 
understanding of them. 

What was said, in the preceding chapter, regarding 
the number of subjects that should engage our attention 
at one time, the propriety of exercise and relaxation, and 
observing the laws of health, are equally applicable to 
the subject of the present; and, in the higher depart- 
ments of original research, a careful attention to them is 
still more requisite, since the mind is more absorbed, and 
the physical energies more prostrated than when we are 
only following in the footsteps of others. Here vigorous 
thinking is generally requisite to success, since feeble and 
superficial efforts will accomplish nothing of consequence, 
though continued for years. 

Few persons will care to turn their attention to every- 
thing worthy of investigation ; and knowledge is best 
advanced by every one's attending to what most inter- 
ests him, as this is generally the subject to which his pre- 
vious pursuits and attainments qualify him to do justice. 
In selecting subjects, the best course generally is, to take 
up those which we can investigate with the greatest 
zeal and perseverance ; for unless we delight in the pur- 
suit, our labors will generally prove abortive. 

The following are the principal requisites preliminary 
to original investigation. 

1. The mental and bodily faculties requisite to success 
in the particular department of investigation. A blind 
man cannot extend the science of Optic, nor a deaf man 
that of Acoustic. So, one who is unable to reason accu- 
rately and continuously, should not attempt new discov- 
eries in Mathematics ; nor should one who is unable to 
analyse thought, attempt to extend mental science. We 
should possess those talents which are indispensable to 
success, before attempting any original investigation: 
otherwise we shall labor in vain. 

2. A precise and accurate conception of the very thing 
of which we are in search. Unless we determine this, 
we must work, in a great measure, at random, and spend 
our time and labor without knowing the exact object of 
our pursuits, so that we shall generally effect nothing of 
any consequence. 

3. A subject xoorthy of our investigation, and within 
the reach of the human faculties. Otherwise we shall 
pursue trifles, or attempt impossibilities, and our efforts 

G2 



154 Original Lswesxigaxiox. [Chap. IX. 

will prove abortive. The difficulty of a subject is no cri- 
terion of its value. It is harder to chew the shells than 
the kernels; yet the latter are by far the more nutri- 
tious ; and the case is frequently the same with knowl- 
edge. That which is obtained with most difficulty, may 
possibly be the least valuable. 

4. A knowledge of precious attainments regarding the 
subject of investigation. Unless we know what has been 
already accomplished by others, we may toil in repeating 
what others previously achieved. 

5. An acquaintance with the various branches of 
knowledge which are related to the subject of examina- 
tion. Otherwise we lack a good guide to direct our in- 
vestigations, since one department always throws light 
on kindred subjects. 

6. A knowledge of the history of that branch to ichich 
the subject under consideration belongs. This will pre- 
vent us from attempting what has already been found to 
be impracticable, and at the same time furnish various 
hints regarding the best mode of proceeding. 

7. Any instruments, tools, or apparatus which may be 
requisite in investigating the subject. Xo progress can 
be made in astronomical observations without telescopes, 
accurate time -keepers, and instruments for measuring 
small angles. So, the chemist requires retorts, heat, and 
reagents. Indeed most of the physical sciences require 
some apparatus in order to extend their boundaries, 
without which success cannot reasonably be expected. 

In making original investigations, we may proceed by 
two different methods: l.We may simply observe and 
record phenomena, including immediate and obvious in- 
ferences, as when we travel through a foreign country, 
and learn its geography, or discover new species of plants 
and animals. This method may be termed direct inves- 
tigation. 2. "We may commence with discernments, as- 
sumptions, or the truths acquired by the preceding meth- 
od, and proceed to trace latent causes or remote conse- 
quences and inferences, forming indirect investigation. 
Such are, the discovery of the real motions of the Earth 
and the invention of a calculating machine. Here it is 
frequently requisite to employ long chains of reasoning, 
and hypotheses, or experiments. This method may be 
subdivided into — indirect discovery, where we ascertain 
new truths otherwise than bv direct discoverv — and in- 



Sec. 2.] Principal Rules. 155 

vention, where we contrive a new combination, or devise 
some new means, for effecting a definite object or known 
end. 

The following are the principal rules applicable to both 
methods : 

1. Obtain clear and distinct comprehensions, so that 
you may know the exact thing comprehended, and dis- 
tinguish it from any other which it may resemble : else 
your knowledge of the subject will be vague and dim, or 
you will mistake one thing for another. 

2. Obtain complete comprehensions / otherwise you 
will think that you understand the whole subject, when 
you see only one side of it ; and serious error will result. 
In order to this, we must look closely to every part of 
the subject, and not turn away from anything because it 
may be displeasing. 

3. Distinguish probability from certainty, and draw 
no inferences but such as necessarily follow from your 
comprehensions: for otherwise you will inevitably fall 
into error. 

4. If you form hypotheses, test them by the proper rules 
for that purpose, that an ei'roneous hypothesis may not 
be substituted for a demonstrated theory. 

5. In classifying your Jcnoicledge, adhere to the princi- 
ples of classification, so that you may avoid the confu- 
sion which will otherwise ensue. 

6. Write down properly, and with the least possible de- 
lay, the remits of your labors, so that y ou may avoid er- 
rors of memory. When some interval has elapsed, pre- 
vious to writing, it should be noted ; and we should em- 
ploy the most appropriate terms for expressing those re- 
sults. 

2. Of Direct Discovert. — Kequisites to Success. — Common Er- 
rors. — Proper Course. — Important requisite, in certain Investiga- 
tions. — Sphere of Direct Discovery. 

This kind of investigation requires sound senses, care- 
ful observation, and an application of the simpler proc- 
esses of generalization, with sufficient judgement to direct 
the mind to proper objects. It is also necessary to pos- 
sess habits of close attention, and of distinguishing phe- 
nomena from inferences or conceptions, so that one thing 
may not be mistaken for another, and what is actually 
seen confounded with what is only inferred or imagined. 



15G Okk.i.nai. Invk.vik.aik'N. [Chat. ]X. 

To guard against such errors, Ave must use the means 
formerly pointed out, for determining what is really com- 
prehended, and what are the direct legitimate infer* i 

In all investigations in the physical and mental sci- 
ences, Ave must beware of the once common practice of 
assuming that things are as avc think they must or ought 
to be, instead of ascertaining how they actually are, which 
may differ widely from the former. We are tempted to 
this course by the comparative ease with which disputed 
or doubtful points may thus be apparently set at rest. 
Another common error is, to gather up all that leads to 
a favorite conclusion, and overlook everything of a con- 
trary tendency, which may possibly be more cogent than 
the former. 

We should observe closely and attentively all that is 
within our reach which has a bearing on the subject, so 
as neither to overlook anything of importance, nor dis- 
tinguish things that are essentially alike, or confound 
things that are otherwise : Ave should record clearly and 
accurately, with the least possible delay, what admits of 
description and is liable to be forgotten : and avc should 
draw no unwarrantable inferences. In order to avoid 
misdescription, Ave must rightly understand the thing to 
be described, and employ suitable terms for that purpose. 
Where avc have failed to make a record at the time of 
observation, Ave should beware of stating more than avc 
distinctly remember, and note the interval between the 
time of observing and writing : otherwise various errors 
Avill probably ensue. 

In those investigations which involve quantity as a 
material element, exact numerations or measurements 
are of much importance, in enabling us to avoid error. 
Many false theories, adopted for centuries, would have 
been at once exploded by the application of this test. 

Although unexplored regions or subjects furnish the 
widest fields for direct discovery, yet there is often am- 
ple room for them elsewhere ; and much that is unknown 
and important may often be learned from proper observ- 
ations, made in places often traversed, but never thor- 
oughly explored, or on subjects often considered, but 
never thoroughly understood. 

§ 3. Of Indirect Discovery.— "Requisites to Success.— Principal 
Fields.— Uses of a knowledge of kindred departments.— How prop- 
er Subjects are discovered. — Next Step. — Extension of tieiieraliza- 



Sec. 3.] Indirect Discover y. 157 

tion. — Analogy. — Proper Course regarding it. — Its Uses. — Abuse 
of Analogies. — Usual course of Indirect Discovery. — Importance 
and means of readily discovering the most probable Hypothesis. — 
Indications of such Hypotheses. — Usual results, where no Proba- 
bility guides the investigation. — How to be avoided. — Importance 
of analysing the subject mentally. — What is frequently the great- 
est Difficulty. — Means of effecting the Analysis. — Mode of proceed- 
ing where we cannot employ Premises strictly True. — Failures. — 
Mode of proceeding where there are several Independent Means 
of testing the Conclusion. — Eules regarding Experiments. — Prob- 
able Consequences of disregarding them. — Requisites before draw- 
ing a final Conclusion. 

In addition to the prerequisites mentioned in the pre- 
ceding section, the successful prosecution of this kind of 
discovery requires that the faculties of Intuition and Con- 
ception should be vigorous, and that the investigator 
should possess great perseverance and the power of con- 
tinued attention. Activity of conception will produce 
only wild theories, unless its operations are controlled by 
close reasoning, and its productions tested by careful ob- 
servation or experiment. Acuteness of apprehension and 
a strong memory are advantageous ; but they are not in- 
dispensable. 

The principal fields of indirect research are, the sciences 
and the arts. The former are so connected that, in or- 
der to be placed in a favorable position for extending 
their boundaries, the investigator should possess a knowl- 
edge of the elements of all that have a bearing on his 
immediate subject, in order that the various things which 
must be considered, may suggest themselves to his mind 
at the proper time. This requires that he familiarize 
himself with them, by repeatedly considering them close- 
ly and attentively. 

The investigator should also be well acquainted with 
the various parts of the subject, as it now stands, and 
able to view them in all their principal relations ; for a 
knowledge of one part is often necessary to a right un- 
derstanding of another, apparently unconnected with it. 
It is only by means of the known that we ascertain 
the unknown : and, therefore, a knowledge of the way in 
which former discoveries were made, of the suggestions 
thrown out by their authors, and of the failures that oc- 
curred, generally furnishes indications of the means by 
which a doubtful or disputed point can be either estab- 
lished or disproved, while it guards us against courses 
which are likely to prove unavailing. 



158 Original Investigation. [Chap. IX. 

Proper subjects for investigation are suggested by the 
deficiencies of some science or art, or the manifest ad- 
vantages of further knowledge, on some point regarding 
which little is still known. 

The next thing is, to ascertain the limits within which 
the proofs are likely to be found ; and here the subject 
itself generally indicates their source, as they are usual- 
ly found in other parts of it, or in kindred branches of 
knowledge. 

Some of the most important additions to knowledge 
consist of the extension of generalization, or of bringing 
a certain law under a superior law. In effecting this, we 
are often aided by analogy, which is, a resemblance tran- 
scending direct apprehension, such as similarity of func- 
tions, origin, tendency, or any other relation. Visible re- 
semblances have seldom a place in these investigations, 
because they are exhausted in forming the lower gener- 
alizations. 

In searching either for analogies or closer resemblances, 
we should first refer to those things which most resem- 
ble the one under consideration, as these are most likely 
to furnish faithful similarities. It is proper afterwards 
to extend our comparisons, in order to reach the higher 
generalizations, or remove doubts or difficulties. Thus, 
some obscure points in Physiology have been cleared up 
by having recourse to Phytology, or that part of Botany 
which treats of vegetable structures. 

The reality of supposed analogies is to be tested by 
observations or experiments ; and the nature of those re- 
quired is generally indicated by the analogy: but the 
proper mode of conducting them often requires great 
skill and dexterity, which is obtained only by some prac- 
tice and a good acquaintance with the general subject. 

The discovery of mere analogies is sometimes a thing 
of great importance as an end, since they furnish proba- 
bilities, which are all that require to be known, in many 
cases. But they are more frequently important as a 
means of extending generalization : for, by discovering 
such resemblances, we are often led to find that things 
apparently very different, are still of the same class. The 
polarity of a magnetic needle has no apparent resem- 
blance to the phenomena of common electricity; yet, 
when we observe that the like poles attract, and the un- 
like repel, each other, as in the case of two excited elec- 



Sec. 3.] Indirect Discovery. 159 

tries, we might suspect that both phenomena belong to 
one general class, a conjecture which has been fully 
established. 

Analogies also guide us in testing hypotheses : for as 
every analogy furnishes a probability of the truth of the 
hypothesis based on it, the closest and most numerous 
analogies indicate the most probable hypotheses, and 
thus aid us in ascertaining the truth. 

Analogies are very liable to produce a belief that the 
resemblances extend farther than they really do, and that 
resemblance in one thing proves a like resemblance in 
another, or that things which perform similar functions 
are themselves similar. They have thus led to various 
errors : and, therefore, we should note the differences, as 
well as the points of resemblance ; otherwise the analogy 
will frequently mislead us. In comparing a bird with an 
ox, we should not infer that the two are of the same 
class, because they have a skull, a spinal column, and a 
double heart, or that the bird's wings are used in moving 
upon the ground, because they are analogous to the ox's 
forelegs. 

The usual course of indirect discovery is, to detect sim- 
ilarities between two or more things, and then test the 
extent of the actual resemblances by means of reasoning, 
observation, and experiment. If the knowledge of the 
mere resemblances be not the ultimate object sought, we 
form hypotheses ; and, after rejecting those which either 
involve absurdities or are incompatible with known facts, 
we determine which is the most probable, by means of 
analogies, and then test it, in the manner already indi- 
cated. Ready skill in discovering analogies is generally 
acquired by means of an accurate and extensive knowl- 
edge of the particular, and kindred, subjects, combined 
with habits of close and careful observation, and a vigor- 
ous power of conception. 

The most probable hypothesis is generally that which 
is most consistent with known truths, and which ac- 
counts, in the fullest and simplest manner, for all the phe- 
nomena. It may possibly be false : yet the best course 
usually is, to test it, before trying any other. 

When there is no probability to guide us, we may still 
observe and experiment: but our labors will generally 
prove abortive, or end in something different from the 
object of our search. A person sometimes stumbles on 



160 Original Investigation. [Chap. IX. 

the right hypothesis at the outset, without ascertaining 
the most probable : but the case is usually otherwise ; 
and indirect discoveries of any consequence are very rare- 
ly made by persons devoid of judgement and perspica- 
city, while they are never accidental. 

In order to success, we must generally analyse the 
subject mentally, and thus ascertain its various parts. 
Things are mostly presented to our immediate observa- 
tion in so complex a form that it is impossible to discov- 
er the object of our investigation, without considering 
the various parts in succession : for nobody can consider 
several points simultaneously, when every one of them 
requires close attention from the same faculty. 

This analysis is equally useful in detecting analogies, 
deducing remote inferences, or establishing hypotheses. 
The greatest difficulty generally lies, not in actually ac- 
complishing the results, but in discovering clearly how 
they are to be effected, and in performing the initiatory 
preparations ; and, in order to this, the mental analysis is 
generally indispensable. It enables us to resolve a com- 
plex or difficult problem into a number of easy steps, 
every one of which prepares the way for effecting that 
which follows ; so that we pass from one to another with- 
out any great difficulty, verifying the different processes 
as we proceed. 

The analysis is generally effected by concentrating the 
attention on a particular point, considering it, in its vari- 
ous aspects, till we clearly see its bearings, then proceed- 
ing to another point, and so on. The points to be select- 
ed for consideration depend on the nature of the subject 
and the object of the investigation. 

In many cases, it is impossible to reach our final object 
from any premises which are strictly true. We, there- 
fore, make an assumption which is partially inaccurate, 
then deduce the consequences, and afterwards discover 
the modifications to be made in our conclusions, in order 
to render them quite accurate. The Astronomer cannot 
determine the future place of a planet by starting with 
the truth regarding the various forces that affect it, as no 
human intellect can solve so difficult a problem. But he 
first assumes that it is influenced solely by the Sun ; and 
he afterwards determines what is due to the disturbing 
influence of the other planets, for which he then makes 
proper allowances. 



Sec. 3.] Experiments. 161 

Much judgement is often required in discovering the 
best course to be adopted, which is frequently done only 
after several other methods have been tried, and failed : 
and, therefore, such failures are to be expected, and must 
not discourage the investigator. They have often pre- 
ceded important discoveries. 

Where we ai'e furnished with several independent 
means of testing the point under consideration, the best 
course generally is, to trace carefully the result to which 
we are led by each, irrespective of the others. If all con- 
duct us legitimately to the same result, the conclusion is 
firmly established. If the results are inconsistent, there 
must be some fallacy in our proceedings, since one sound 
conclusion cannot possibly be inconsistent with another ; 
and we should search till we detect the error. If some 
of the processes merely fail to give any reliable result, 
while others conclusively establish the point, the nega- 
tive results are entitled to no weight. 

Experiments frequently furnish important aid in this 
class of discoveries ; and the following general rules will 
assist us in their application : 

1. Form a clear and precise notion of the object of the 
experiment, or the purpose which it is designed to ac- 
complish. 

2. Remove, as far as practicable, every source of doubt 
or uncertainty regarding the result, so that it may be as 
unequivocal as possible. 

3. Test the inferences which the result seems to war- 
rant, by the principles of sound reasoning, so as to obvi- 
ate fallacious conclusions. 

4. Where a result is equivocal, or otherwise unsatisfac- 
tory, repeat the experiment, with such variations as seem 
best calculated to remove the difficulty. 

5. If the result should still continue unsatisfactory, 
adopt, if practicable, a different hind of experiment, 
which promises to obviate the difficulty. 

If these, or similar, rules are not observed, the results 
will be more likely to rivet error and conceal truth, than 
to dissipate the former or establish the latter, since prej- 
udice will persuade the investigator to adopt its own dic- 
tates, and reject hostile, though necessary, inferences. 

Before drawing a final conclusion, we should have sat- 
isfactory proof that we know everything requisite to a 
right view of the subject under investigation : otherwise 



162 Original Investigation. [Chap. IX. 

we shall probably adopt some theory which misrepre- 
sents the subject. Most of the objectionable theories 
ever broached were owing, in a great measure, to ignor- 
ance of some important parts of the subject, which were 
overlooked. 

§ 4. Of Invention. — Relations of Invention to indirect Discovery. — 
Use of Analogy. — Inventions of two kinds. — Principal fields of In- 
vention. — Mathematics.' — Physics. — Education. — Social Institu- 
tions. — Requisites in Inventions immediately regarding Man. — 
Why Legislative and Social have not kept pace with Physical In- 
ventions. — External aids of Invention. — How the place of Models 
may be supplied. 

Invention resembles indirect discovery so much that 
the remarks made in the preceding section are mostly 
applicable to it. The principal difference is, that we 
have here to contrive some means of solving a given 
problem, instead of discovering a proof or refutation of a 
given proposition, or deducing remote inferences. Hence 
there is rather less occasion for simple observation or 
comparison, and Ave are more dependent on an extensive 
and familiar acquaintance with the subject of investiga- 
tion, and the power of readily forming conceptions and 
testing them by reasoning and experiments. 

Analogy is generally less available than in discovery : 
yet it is often of great use, particularly in the earlier 
stages ; and many important inventions originated in ob- 
serving the modes in which certain ends are effected by 
natural means, a source of assistance which cannot easily 
be exhausted. 

Inventions are either physical or mental. The former 
consist chiefly of tools or machines, such as saws, planes, 
files, ships, clocks, and steam-engines. The latter consist 
of means for enabling us to acquire or retain knowledge, 
or to perform some process with correctness and dis- 
patch. Such are, the ordinary rules of Arithmetic, and 
all those arts in which the processes are not obvious or 
dependent on machinery, and also the modes of influenc- 
ing emotions and opinions. 

The principal fields of invention are, the mathematical 
and physical sciences, education, social institutions, and 
the arts. 

The objects of mathematical invention are, the solution 
of problems, or the application of Mathematics to extend 
the boundaries of Physics. In some cases, modes of ef- 



Sec. 4.] Invention. 163 

fecting the desired results are already known ; but they 
are too tedious, or not sufficiently accurate, or too liable 
to lead us into error. In such cases, the inventor's la- 
bors are requisite, until he has discovered the means of 
effecting the desired results with the greatest attainable 
quickness and accuracy. 

In the physical sciences, the fields of invention are 
widest where the application of Mathematics is most ex- 
tensive. But there is room for improved methods of 
making observations and experiments in others also; 
and these are the principal means by which they can be 
corrected and extended. A wide field for physical in- 
vention is furnished by the application of the various 
natural forces or powers to produce desired results, in- 
cluding those of gravity, expansion and contraction of 
substances by differences of temperature, chemical ac- 
tion, heat, light, and electricity. The inventor will de- 
rive much aid from studying the effects produced by 
these agencies, under the various circumstances in which 
they operate. 

The principal subjects of invention, in education, are, 
the best means of disciplining and instructing youth, so 
that all the faculties may be properly developed, while 
the pupil, at the same time, acquires the elements of use- 
ful knowledge. No system of education is satisfactory, 
unless it effects both of these objects, which are so re- 
lated that the same system which best secures the one, 
is also the most favorable for accomplishing the other. 

In social institutions, the principal subjects of inven- 
tion are, public and private law. The aims of invention, 
in relation to the former, are the two following: 1. To 
ascertain that form of government which will be most 
favorable to the enactment, enforcement and perpetuity 
of the best private laws. 2. To determine the best laws 
for regulating the intercourse between different nations 
and their subjects, so that it may be as safe, free and mu- 
tually advantageous as possible. 

In all inventions of which man is the immediate sub- 
ject, the investigator should be guided by a correct and 
extensive knowledge of human nature in general: other- 
wise his inventions will possibly be suitable only for im- 
aginary beings. Another important requisite, in all in- 
ventions of this kind which are intended for immediate 
practice, is, a knowledge of the peculiar characteristics 



164 Original Investigation. [Chap. IX. 

and circumstances of the parties for whom they are de- 
signed. A system of education or government, for in- 
stance, may he the best possible for one community, and 
decidedly objectionable for another, owing to the wide 
disparity in their characters and circumstances. 

Improvements in social institutions have not generally 
kept pace with those in physical science, because the 
laws on which they should be based are not so easily dis- 
covered, and the pursuit has generally been conducted 
against the influence of strong prejudices and external 
disadvantages. Yet these difficulties do not render pro- 
gress impossible. 

In all inventions, we may be aided by writings, draw- 
ings, and experiments ; and, in several, chiefly of the 
physical kind, we derive much assistance from models, or 
actual representations of the proposed invention. The 
faculty of Conception is seldom so powerful that it can 
figure forth and clearly discern, at a single effort, all the 
parts and relations of a complex invention. Hence the 
inventor first makes a representation of his present con- 
ception ; and when he has this clearly before him, im- 
provements and additions are easily planned and effect- 
ed. A carefully constructed model, after being fairly 
tried, generally gives us a good view of the defects and 
merits of the invention, as it now stands, and suggests 
improvements better than anything else, short of a long 
practical trial. 

In many cases, experiments and the construction of 
models are impracticable; yet simple observation may 
answer the same purpose. Thus, if a certain scheme of 
social organization has occurred in History, in circum- 
stances which gave it a fair trial, and it was found to 
fail, no model or experiment is requisite. 



Sec. 1.] Sources and Applications, &c. 165 



CHAPTER X. 

OF CAUSES AND EFFECTS. 

§ 1. Sources and Applications of the Knowledge of Causes 
and Effects. — Two classes of Causes, and means of ascertaining 
them. — Experience, when requisite, and when not. — Advantages 
of knowing the Laws of Nature. — Inadequate Agencies. — Means 
of determining a Cause indirectly. — Important application of the 
Laws of Causation. — Advantages of a knowledge of Controlla- 
ble Causes — and of Causes beyond Control. — Importance of know- 
ing what Effects will be produced by a given Agency. — Tracing the 
implied Consequences of a known Agency. — Moral bearings of a 
Knowledge of Causes. — Cause and Effect signs of each other. — 
Important Distinction, and Practical application. — Caution. 

Causes may be divided into necessary and contin- 
gent. The former consist of those whose existence is 
discerned intuitively, without any direct aid from Com- 
prehension : the latter include those whose existence and 
nature cannot be known without the aid of experience, 
although, as causes are distinguishable from mere phe- 
nomena, they are never discovered without the applica- 
tion of Intuition. 

Contingent causes cannot generally be discovered with- 
out the aid of observation or experiment, since there are 
several agencies to which the effects or phenomena may 
be attributed, and experience alone can inform us which 
is the actual cause. Thus, if a rock roll down from its 
former fixed position, on a mountain's side, we know in- 
tuitively that there must be some cause for the change : 
but what the particular cause is, must be learned from 
the circumstances of the case. 

On the other hand, the existence and general natitre 
of necessary causes are known solely by Intuition. Thus, 
Ave know that the voluntary acts of a man are caused by 
motives, which must be objects that he deems desirable. 
So we know, independently of experience, that the causes 
of our ordinary apprehensions are, external substances, 
distinct from ourselves, and that an exquisitely finished 
time-keeper is the production of skill, and neither of 
chance nor of a bungling artisan. Wherever the phe- 



166 Causes and Effects. [Chap. X. 

nomenon is such that Reason can demonstrate it could 
proceed only from a particular kind of agency, "\ve do not 
require the aid of experience to teach us that it is the 
effect of such an agency. 

Although experience generally lies at the root of our 
knowledge of the particular cause of an occurrence, yet 
we need not have recourse to it, in every case, in order 
to ascertain the very agency concerned. For, when once 
Ave have found out that all the changes which usually 
take place in nature, are immediately owing to certain 
agencies, and that these act with great uniformity, we 
can frequently determine the cause of a phenomenon, 
without any elaborate investigation. Thus, in the case 
mentioned above, if we know the effects of freezing wa- 
ter, and that the fall of the rock was preceded by a se- 
vere frost, we have at once an explanation of the occur- 
rence ; and Avhen we see a rainbow, we know its cause, 
without any investigation. 

A knowledge of the laws of nature frequently enables 
us, not only to ascertain readily the cause of a phenome- 
non, but also to exclude possible causes, as being inade- 
quate, when the particular cause is still undetermined. 
An agency is inadequate when the laws of its operation, 
or its want of skill or power, are incompatible with the 
supposition of its being the cause of the phenomenon in 
question. Thus we cannot attribute warm weather to 
the position of the Moon, because it neither gives out 
nor produces any heat itself, nor does it influence that 
imparted by the Sun, in any measurable degree. 

A knowledge of the requisites necessary to produce a 
certain result, enables us to determine the nature of a 
cause of which we have no direct knowledge. Thus, we 
judge of the skill of a mechanic solely from a view of his 
handiwork ; and we ascertain the force of volcanic ac- 
tion by witnessing the effects which it has produced. 
Thus, also, we ascertain the motives and characters of 
men, when there are no reliable means of doing so di- 
rectly, from continued observation of their conduct. The 
nature of the inapprehensible cause is learned from its 
effects, as the quality of an unseen tree is known by its 
fruits. 

A knowledge of the cause of a phenomenon enables us 
to modify it at pleasure, wherever we can control the 
former. Thus, if a certain disease is found to be caused 



Sec. 1.] Applications of Knowledge. 167 

by miasms, arising from a marsh which can be drained, 
we can stop its ravages whenever we like ; and if a pub- 
lic speaker knows what causes will produce certain emo- 
tions in his hearers' minds, and can apply them, he may 
produce these emotions at pleasure. 

Where the cause is not directly under our control, a 
knowledge of its nature may still enable us to counteract 
its influence. Thus, we may neutralize the effects of 
miasms which we cannot remove, by avoiding those ex- 
posures and excesses which render us peculiarly suscepti- 
ble of their influence; or we may directly counteract 
them, by artificial heat or warm clothing. 

When the object is, not to avoid, but to secure, effects 
whose causes are not under our control, a knowledge of 
these causes aids us in finding that of which we are in 
search. Thus, a knowledge of the origin of coal directs 
us to look for valuable mines only in such rocks as were 
deposited while vegetation was very luxuriant; and it 
informs us that no coal whatever is to be found in the 
non-fossiliferous rocks, and that no extensive deposits can 
be expected either in the oldest fossiliferous rocks or in 
those of recent formation. 

When the cause is beyond even our indirect control, a 
knowledge of its existence and nature may still enable us 
to keep beyond the reach of its influence, and thus avoid 
the pernicious effects. If a person has contracted a dis- 
ease, by living in a very damp locality, he may possibly re- 
move to a dry atmosphere, and thus get well, whereas, 
if he knew not the cause of his ailment, or attributed it 
to some imaginary agency, he would be more likely to 
be injured than benefited by attempts to effect a cure. 

It is equally important to know what effects will be 
produced by a given agency, acting in peculiar circum- 
stances. A knowledge of the properties of steam and 
electricity enables us to produce results that would once 
have appeared incredible ; and, by knowing the effects 
of certain mental agencies, we can influence the views, 
feelings, and conduct of others, and remove what is bad, 
or improve what is weak or defective, in our own char- 
acters. 

A knowledge of the nature of a certain agency often 
enables us to ascertain the existence of effects, of which 
we have no other evidence except that they must result 
from the agency. Thus, many facts in Astronomy were 



168 Causes and Effects. [Chap. X. 

discovered, as necessary effects of the force of gravity, 
before they were known by observation. 

By deducing the implied consequences of a known 
agency, we can often discover other truths, beyond its 
mere effects. Thus, the effect of the valves in the blood- 
vessels is simply to check a retrogressive or backward 
course of the blood, as it circulates in the arteries and 
veins ; and this is, no doubt, the object for which they 
were formed: but, by investigating this object, Harvey 
discovered the circulation of the blood ; and other im- 
portant physiological discoveries have been made in the 
same way. 

A knowledge of causes is as important in its moral 
bearings as in any other. "When we view an admirable 
piece of mechanism, and understand the skill and dexter- 
ity necessary to plan and execute it, we partake, through 
sympathy, in a greater or less degree, of the emotions of 
him who produced it : for these feelings are evidently de- 
pendent on a knowledge of the causes that produced the 
results, and proportional to its extent and accuracy. It 
is for this reason that a good artisan beholds a master- 
piece with much greater pleasure than one who supposes 
that such things can be produced as easily as common 
tools. 

The most important aspect of this subject is, that which 
regards the works of the Eternal Architect. These are 
incessantly presented to our view, in vast profusion, and 
under an immense diversity of forms, from the depths of 
the Earth (whence have so often issued streams of liquid 
lire, bearing the elements of future fertility, mixed with 
iron, gems, and gold) to those remote constellations 
whose numbers, sizes and distances are so great that the 
contemplation of the whole amazes and confounds the 
mind. 

Not only does a knowledge of the agencies that oper- 
ate in nature, enable us to supply many defects in our 
knowledge of its phenomena, and to form a more correct 
and extensive notion of the creation than is otherwise 
possible, but, when we understand the difficulties w T hich 
have been overcome, in accomplishing the results that we 
behold, and learn the origin and purposes of the various 
parts, we obtain an effective knowledge of the Most High, 
and partake of those emotions which unite us to our Cre- 
ator, and which alone can satisfy man's immortal mind, 
when nil lower enjovments shall have ceased. 



Sec. 2.] Applications op Knowledge. 169 

As cause and effect, or the common effects of a cause, 
are inseparably connected, wherever there is no interfer- 
ing or counteracting agency, they are signs of each oth- 
er ; and, therefore, when one is known to operate or ex- 
ist, the other may be inferred. It is thus that the geolo- 
gist discovers the causes of phenomena long after they 
have ceased to operate. So, a physician learns the ori- 
gin, character, and future course, of a disease, from pres- 
ent symptoms; and a statesman sometimes foresees fu- 
ture events, as the effects of existing agencies. In this 
way we learn many past and future contingencies, since 
they are connected with the present as cause and effect, 
or successive effects of a common cause ; and we may fre- 
quently learn the present unseen from the seen, since the 
one either produces the other, or both are contempora- 
neous results of the same agency. 

We must distinguish a knowledge of the effects of cer- 
tain agencies, or of the causes of particular phenomena, 
from that of the mode in which the causes operate. We 
may possess the former, while we are quite ignorant of 
the latter. Thus, we may know that certain poisons 
speedily destroy life, without knowing how they do so, 
just as we know that we move our limbs at pleasure, al- 
though the mode in which we do so, is a profound mys- 
tery. 

The value of the former kind of knowledge is evident- 
ly independent of the latter, and it may be of the utmost 
importance, though we should continue quite ignorant 
of the mode of operation. This, however, is a legitimate 
subject of inquiry, though we shall often find that we can 
make little real progress in the investigation. Words 
have sometimes been freely employed, in such cases, 
while those who used them had no clear idea of what 
they meant by them. 

§ 2. Various Kinds of Causes. — Efficient and Conditional Causes. 
— Immediate, Mediate, and Ultimate Causes. — Only Ultimate 
Causes. — Common Error. — Remarks on the Laws of Nature, and 
on Ultimate Causes. 

All causes are either efficient or conditional. The for- 
mer consist of those forces which actually produce the 
effects, and are otherwise termed powers : the latter are, 
the circumstances or conditions which are requisite to 
the production of the effects ; and thev are also termed 

H 



170 Causes and Effects. [Chap. X. 

occasioning causes, or simply conditions. In popular 
language, that is generally termed the cause which is 
most subject to change, whether efficient or conditional. 
Thus, if a man slips, when walking on ice, his fall is said 
to be caused by its slipperiness, although this is only a 
conditional cause, while the force of gravity is the effi- 
cient cause. 

Causes, again, are immediate, mediate, or idtimate. 
The immediate cause is that which directly produces the 
result, without the intervention of any second agency. 
The idtimate cause is, the good or evil which originates 
the volition that leads to an effect. A mediate cause is 
one that intervenes between the ultimate and the imme- 
diate cause, and forms a necessary link in the chain. 
When a blacksmith hammers a bar of iron, the stroke 
of the hammer is the immediate cause ; the thing which 
led him to will the hammering is the ultimate cause ; and 
the movements of his arm are an intermediate cause. 

The causes of volitions are the only ultimate causes, 
since eternal spontaneous motions of inanimate beings 
would be effects without any adequate causes ; and, if 
such beings are at rest, they will evidently move only as 
they are moved. Hence, although they often communi- 
cate, they never originate motion, either in themselves or 
in other beings. 

When a phenomenon has been shown to belong to a 
known class, it is often thought that its ultimate cause 
has been unfolded, while, in fact, no explanation has been 
given of any such cause. Thus, when certain motions 
of the Moon are traced to the force of gravity, many 
think that their ultimate cause has been explained, where- 
as the law of gravitation explains neither the nature nor 
the origin of the force which produces those motions. (15) 

Most of the laws of nature are merely inductions re- 
garding occurrences or phenomena, and give no expla- 
nation of any cause whatever. When we say, for in- 
stance, that " metals expand, on the application of heat," 
we do not explain why any of them does so. Even those 
laws of nature which express causes, seldom explain the 
idtimate cause. Thus, it is a law of nature that " heat 
expands gases ;" but this does not explain why it does 
so ; for heat is as destitute of thought as the gases. 

In several branches of Physics, it is not necessary to 
investigate idtimate causes ; but, even there, it is a seri- 



I 



Sec. 3.] Methods of Discovering. 171 

ous error to suppose that we know more of the matter 
than we actually do ; aud, in many physical researches, 
the consideration of ultimate causes is of much use in 
promoting discovery. In the mental sciences, the sub- 
ject is one of the utmost importance. 

§ 3. Methods of determining Causes and Effects. — Divisions of 
the subject. — Inadequate and absent Agencies. — Effect attributa- 
ble to only one Cause. — Case of combined Agencies. — Means of 
determining the influence of each. — Application of the fact that Ef- 
fects follow their Causes. — Proper course when Cause and Effect 
appear simultaneously. — Application of a knowledge of the Laws 
of Nature. — Frequent means of ascertaining the existence or ab- 
sence of possible Agencies, and the effect or intensity of a known 
Agency. — Caution. — Proper course regarding known and un- 
known Agencies. — Seven Principles applicable where preceding 
methods fail, with Remarks. — Proper course where one Principle 
gives equivocal Results. — Sole and combined Agencies. — Means 
of ascertaining the nature and extent of a particular Agent's influ- 
ence. — Use of Analogy. — Common Mistake. — Use of Experiments. 
— Effects which cannot be traced to any known Cause. — Errors 
regarding them. — Mode of tracing a chain of Causes. — Means of de- 
termining what Causes would produce a supposed Effect. — Modes 
of ascertaining the effects of a known Cause. — Use of Experiments 
in such cases. — Proper course where these are inapplicable. — 
Means of tracing the Effects of Causes which have ceased to oper- 
ate. — Independent Effects. — Cases of Reciprocal Action. — General 
Requisites, and Cautions. 

All inquiries regarding causes and effects are neces- 
sarily either into the causes of known or supposed effects, 
or into the effects of known or supposed causes ; and 
each inquiry contains three subdivisions, which may be 
stated as follows : 

A. 1. What causes, now inoperative, have produced 
known effects. 2. What causes, now operating, produce 
known effects. 3. What causes would produce certain 
supposed effects. 

B. 1. What effects have been produced by known 
causes, no longer operative. 2. What effects known op- 
erating causes are now producing. 3 . What effects would 
certain supposed causes produce. 

Both classes of inquiries are based on the same general 
principles, so that we need not discuss every subdivision 
separately. In many cases, also, we do not know before- 
hand whether the causes are still operative or not, as 
that can be learned only when we have ascertained what 
they really are. 



172 Causes and Effects. [Chap. X. 

The two intuitions that a cause must be adequate to 
produce the effect, and that it cannot act where it is not, 
except by a medium, frequently enable us to exclude 
many possible agencies from the list of admissible causes. 
Thus, the vapors arising from cooking utensils cannot be 
the cause of heavy rains ; and a man who was in China 
when a murder was committed in New York cannot 
have had any direct hand in it. In applying those in- 
tuitions, however, we should ascertain that the agency 
in question is inadequate or absent : for this has frequent- 
ly been assumed where the case was otherwise. 

In many instances, the circumstances are such that an 
effect can be attributed only to one cause. These are 
chiefly where we know that no other adequate agency 
operates in producing the result. Thus, the immediate 
cause of the change of seasons must be solely the differ- 
ent directions of the Sun's rays, since there is no other 
agency which has even a tendency to produce those 
changes. But we should know that no such agency ex- 
ists : for we are liable to assume this, when we are sim- 
ply ignorant of the existence of any such cause, while we 
may erroneously assume something else as the cause, 
which is a mere antecedent or concomitant. The requi- 
site knowledge is generally obtained by extending our 
observations, or repeating our experiments, until the sup- 
position of casual or latent agencies is excluded. 

A certain agency frequently operates in producing a 
result, while it is only one of several causes, each of which 
may be inadequate to produce the effect : and, therefore, 
before we can legitimately conclude that an effect is pro- 
duced solely by a single agency, we must know that no 
other contributes, in any degree, to produce the result. 

Where several agencies co-operate, it is often import- 
ant to ascertain their comparative influence. This is to 
be done, either by reasoning from intuitive principles, or 
by observing the force of each, where it acts singly. All 
we can ascertain, in many cases, is, that one agency is 
much more potent than another ; but this usually answers 
the purpose, and greater accuracy is of little consequence. 

Where the agents are different in their nature, and 
every one is essential to the production of the effect, we 
cannot even institute a comparison between their respect- 
ive influences. Thus, we cannot rightly say that food is 
more essential than water to sustain life, since each is 



Sec. 3.] Methods of Discovering. 173 

indispensable. But where the agents are alike in kind, 
and their power admits of measurement, while the effects 
of one are only cumulative to those of another, we may 
possibly ascertain the exact amount due to each. Thus, 
when several steam-engines are employed to drain a pool, 
it may be easy to ascertain the exact amount of water 
removed by each. « 

Where several similar causes unite in producing a cer- 
tain result, the total effect is generally a combination of 
the separate results. If two mechanical forces act in the 
same direction, the combined force is equal to their sum ; 
and, if they act directly against each other, the result is 
equal to their difference. But experience is often neces- 
sary, in order to determine the actual results : for there 
are various exceptions to the general rule. White light, 
for example, is a combination of blue, yellow, and red, 
each of which is much darker than the compound. 

Every effect is necessarily preceded by its immediate 
or mediate cause ; and this often enables us to determ- 
ine whether a particular agency is concerned in produc- 
ing a certain result. For, if the agency appears subse- 
quently, or even simultaneously, it cannot be the cause. 
But when an agent acts continuously, and the effect ap- 
pears in the same manner, cause and effect appear simul- 
taneously, although every part of the effect succeeds the 
particular act by which it is produced. Here we must 
compare the time when the cause began to operate with 
that when the effect first appeared, and the time when 
the former ceases to act, with that when the latter ceases 
to appear. 

The peculiar nature of many agents excludes them 
from the supposition of their being concerned in produc- 
ing certain results. For experience, and the intuitions 
of causation, inform us that they either are neutral, or 
that their results differ materially from the object in 
question, or that they are even the reverse. We cannot 
consider the geological formation of a country the cause 
of the change of seasons, or unstratified rocks as the re- 
sults of aqueous deposits, or light the cause of darkness. 

This method of limiting the possible causes of an ef- 
fect supposes that we already know the characteristics 
of the various agencies ; and hence it becomes more ap- 
plicable as knowledge advances. Owing to their gen- 
eral ignorance, rude nations have often assigned agen- 



1 74 Causes and Effects. [Chap. X. 

cies as causes of results with which an intelligent person 
would readily know that they have no connection. Pieces 
of human mummy, ground to a powder, were long con- 
sidered excellent medicines for certain disorders, al- 
though everything of that kind is as useless for any such 
purpose as it is disgusting. 

An extensive knowledge of the laws of nature enables 
us, not only to exclude certain agencies from the list of 
admissible causes, but also to conjecture the actual cause, 
amid many which are not absolutely inadmissible. Thus, 
by knowing the properties of water and heat, we can 
readily ascertain the causes of many geological phenom- 
ena. A knowledge of those laws also aids us in determ- 
ining when an unexplained phenomenon is to be atti'ib- 
uted to some agency previously unknown, and in form- 
ing an accurate conception of the nature of that agency. 

The existence or absence of a possible agency may fre- 
quently be ascertained by observing whether or not its 
constant effect is present, on the principle, formerly stated, 
that the presence of an effect proves the existence of its 
cause, and the absence of an effect proves the absence 
of its cause. Thus, the formation of* ice on the waters 
proves that the weather has been cold, and its absence 
proves the reverse. In applying this principle, we must 
beware of assuming, without proof, that an effect can 
have proceeded only from a particular cause, or that the 
phenomenon in question is a constant effect. We should 
also ascertain that there has been no extraneous inter- 
ference with the agencies or phenomena, either accident- 
ally or from design. 

In determining the effect or intensity of an agency, 
we are guided by the intuitions that like effects icill fol- 
low, in the same circumstances, and that cm effect xohich 
depends solely on a particular cause, varies in proportion 
to the changes in the cause / and changes in the effect 
must have been preceded by corresponding changes in the 
cause. Thus, a knowledge of one element enables us to 
know the amount of the other. But we must know that 
no other agency is concerned : otherwise our conclusions 
may be very erroneous. Heat generally expands liquids ; 
but it contracts water, when near the freezing point; 
and when it reaches the boiling point, instead of farther 
expanding, it evaporates in the form of steam. 

In searching for the cause of a phenomenon, we should 



Sec. 3.] General Principles. 1*75 

first ascertain whether it is not produced by some known 
or familiar agency : for, until this is done, we can evi- 
dently have no proof that it results from an unknown or 
new agent. We should make no assumptions in favor 
of either class of agencies, but be guided by probabilities 
and proofs. The mere fact that a certain agency oper- 
ates, does not prove that it is the cause of a particular 
phenomenon, with which there is no proof that it is con- 
nected, and which may be wholly produced by some oth- 
er agency. 

Where none of the preceding methods furnishes the 
requisite information, we must have recourse to farther 
observations or experiments : but sometimes the former 
are sufficient, and the latter are impracticable : in other 
cases, these afford the readiest means of solving the prob- 
lem. In all cases of this kind, important aid may be de- 
rived from the following principles, which are only mod- 
ifications of those of causation, already stated. 

1. The effect must always appear where the agency op- 
erates freely, and never appear where it has not previous- 
ly acted. Hence, if the supposed cause is found to act 
freely, without being followed by the effect in question, 
or if this is found to exist, where the agency has not op- 
erated, it cannot be the cause. 

2. The commencement of the free action of the agency 
must be followed by the appearance of the effect, where all 
other things continue the same as formerly / and the ef- 
fect must cease to be directly produced, when the agency 
ceases to operate. Hence, where the supposed cause com- 
mences to act freely, and the effect in question does not 
begin to appear, or where this does not cease to be di- 
rectly produced, when the supposed cause has ceased to 
operate, the agency is not the cause. The continued mo- 
tion of a body, after it has once been moved, seems to 
contradict this principle : but, in reality, it does not ; for 
the motion is only a continuation of the body's preced- 
ing state, without any additional effect. When a moving 
body changes either its direction or its velocity, there is 
a change, for which there must be some adequate cause : 
but a continued motion, in one direction and with a uni- 
form velocity, is all the unchanging effect of the agency 
which first communicated the motion. 

3. Changes in the agency must be followed by corre- 
sponding changes in the effect ; and changes in the effect 



176 Causes asd Effects. [Chap. X. 

must have heen preceded by corresponding changes in the 
agency. Hence, if one change "without any correspond- 
ing change in the other, the agency is not the cause. It 
must be observed, however, that, in both cases, the cor- 
responding changes are not necessarily similar: and, in 
fact, although they frequently are so, the case is often 
otherwise. Thus, a certain degree of heat produces a 
pleasant sensation, while a great degree produces pain. 

4. TJie presence of the peculiar effects of a certain agen- 
cy proves its previous action / and the absence of its uni- 
form results proves the reverse. Hence, where the for- 
mer are found, the action of the supposed cause is estab- 
lished, and where the latter are wanting, it is disproved. 

5. The time that elapses between the action of the agent 
and the appearance of the effect, must conform to the na- 
ture of the agent and the thing on ichich it operates. 
Hence, if the intervening time be greater or less, the sup- 
posed agency is not the cause. Thus, fire directly ap- 
plied to gunpowder must cause an explosion immediate- 
ly or not at all ; and a man caunot have died from the 
effects of a little arsenious acid swallowed seven years 
previously, while the decease of one who dies instantly 
after taking a few grains of that substance, must be ow- 
ing to some other cause. 

6. Voluntary acts must proceed from motives Jcnoicn to 
the agent, and must harmonize with his character. A 
motive wholly unknown to an agent, or one to which he 
attaches no weight, cannot influence his conduct. Thus, 
brutes are never influenced by a regard for a future state, 
and a thoroughly selfish man never makes great sacri- 
fices purely from philanthropic motives. 

7. The motive must be adequate, icith reference to the 
agent's vieies and belief. A motive may strongly sway 
one person which would have little influence with anoth- 
er. Hence, we must ascertain, not only that the agent 
knew of the supposed motive, and that it harmonizes 
with his character, but that it is one which may have 
produced the effect in question, under the circumstances. 
A miser readily makes great sacrifices for money : but 
he will not knowingly barter everlasting bliss for it, as 
this is an impossibility ; and hence the absurdity of the 
stories that certain persons deliberately made a compact 
with the devil, to be his forever, on condition of his im- 
parting to them certain magic powers. Xor can a miser 



Sec. 3.] General Principles. 177 

be supposed to have been influenced by the desire of 
gain, when he must have seen that the consequent pecu- 
niary loss would inevitably be much greater. 

The preceding principles all assume that the agencies 
operate freely, or without any counteraction, and that no 
conflicting or extraneous agencies interfere with the or- 
dinary results : and they are applicable only upon these 
conditions. 

There is an evident necessity for an agent's conform- 
ing to one or other of the preceding tests, in order to 
proving that it is a cause, and not merely an antecedent 
or concomitant, supposing that there is no other satis- 
factory proof. Its unequivocally fulfilling one of those 
conditions, may furnish the requisite proof. But the ev- 
idence of one is frequently unsatisfactory, owing to the 
narrowness of the phenomena, or the intei'ference of ex- 
traneous or counteracting agencies, or our investigations 
having been either too limited or not conducted properly. 
Here we should apply other tests, and continue our re- 
searches, till we find some conclusive proof. We should 
first try the most probable cause, and, if the result be ad- 
verse, try the next most probable, and so on, till we ei- 
ther discover the true cause, or find that it lies wholly 
beyond our former conceptions. The principle that sim- 
ilar effects generally spring from, similar causes will fre- 
quently suggest the nature of the unknoAvn agency ; and 
further aid may be derived from the proper application 
of hypotheses. 

In order to establish an agent as the sole cause, it must 
appear that the result is unaffected by changes in the 
other agents that might possibly be concerned in its pro- 
duction. When it is found that several agents are joint- 
ly concerned, we should test the interference of others, 
as if the combined group were a single agent. We find 
what agents are joint causes of a result, by testing each 
of them separately, until we have ascertained all that are 
so concerned. 

In investigating the causes of the ordinary decompo- 
sition of organic substances, for example, we first find that 
a certain amount of heat is requisite, as one cause : for 
wherever water freezes, decomposition ceases. Again, 
we find that moisture is requisite: for decomposition 
never proceeds without the presence of water, either in 
the liquid or in the gaseous form. Lastly, we find that 
H2 



17? Causes a>td Effects. [Chap. X. 

air is another requisite : for wherever it is removed, as 
in the exhausted receiver of an air-pump, decomposition 
does not take place. 

Thus we find that ordinary decomposition requires the 
presence of heat, moisture, and air ; and, as it always pro- 
ceeds where these are present in sufficient quantities, and 
without any counteracting agency, these are the only 
causes, although other agents may accelerate or retard 
their influence. The nature of the process is shown by 
comparing its products with the substances previously in 
contact. We thus learn that some of the organic com- 
pounds are decomposed, and unite with the gases that 
compose air and water. 

The nature and extent of a particular agent's influence, 
where it co-operates with others, is ascertained by com- 
paring the result produced where it acts with what ap- 
peara where it is absent or inoperative. Thus, the influ- 
ence of atmospheric resistance on falling bodies or pro- 
jectiles, may be determined by comparing the ordinary 
phenomena with those produced by experiments per- 
formed in a vacuum. 

In many instances, the agent always operates, but with 
very different degrees of intensity. Here its influence 
may frequently be ascertained by the third of the above 
principles. Thus, it is impracticable to produce a per- 
fect vacuum ; yet the influence of the atmosphere may be 
ascertained from observing the variations in the bodies' 
motions, as the density of the resisting medium varies. 

In searching for the cause of a known phenomenon, 
we are often aided by analogy, as like effects generally 
spring from like causes. But we should guard against 
the erroneous supposition that causes resemble their ef- 
fects. There is nothing in a musical instrument or its 
motions that resembles its sounds, nor is there anything 
in a rose resembling its odor or color; and so of all our 
senses. Yet this error has prevailed extensively, owing 
partly to the common tendency to confound cause and. 
effect, and partly to overlooking the wide difference be- 
tween direct resemblance and corresponding intensity. 
The effect generally varies as the intensity of the cause : 
but this no more proves resemblance than the fact that 
the more a man spends, the less he has, proves that wealth 
resembles poverty. 

Although experiments cannot aid us directly, in as- 



Sec. 3.] General Principles. 179 

cending from an effect to its cause, yet they frequently 
enable us to test the influence of a possible agent, in pro- 
ducing the effect : for we have only to put it into opera- 
tion, and note the results. Thus, if* we are investigating 
the origin of basaltic columns, we may take some of the 
rock, melt it, and allow it to cool under pressure. If we 
now find that a columnar structure results, we have as- 
certained one cause which may have produced the phe- 
nomenon in question. 

A single experiment of this kind, however, teaches us 
only that such an agency was probably the cause, except 
where there is no other admissible cause : and, therefore, 
it generally requires repeated experiments, to determine 
the question. Thus, if we are investigating the origin 
of mineral veins, we may try if we can produce such phe- 
nomena from aqueous deposits. When this experiment 
gives a negative result, we may try chemical precipita- 
tion. If this should fail, we may try electro-galvanic 
agency : and if this fail, we may try the influence of sev- 
eral agencies combined. 

When it is found that an effect is not produced by any 
known cause, it must be attributed to some new kind of 
agency, whose nature is to be ascertained by observation 
or experiment and testing hypotheses. Here we must 
beware of adopting an agent as the cause without con- 
clusive proof, as we are liable to assign imaginary causes, 
many instances of which occur in the scholastic philoso- 
phy. The descent of heavy bodies, for instance, was at- 
tributed to a natural tendency downward, just as the 
phenomena of gravitation have been more recently at- 
tributed to a natural tendency of bodies to move towards 
each othei", whereas no such thing exists, the natural 
tendency of bodies being to remain as they are, and nei- 
ther to move nor to stop moving, except as they are 
made to do so. 

In tracing a chain of causes, the easiest course gener- 
ally is, to ascertain first the immediate cause, and then 
the succeeding causes successively, in their order. Thus, 
the real motions of the planets are the immediate cause 
of the phenomena which they present to our view. Those 
being determined, the next point was, to ascertain the 
causes of these motions ; and when this was done, the 
law of gravitation still remained to be accounted for. 
Supposing it should be traced to undulations of ether, 



180 Causes and Effects. [Chap. X. 

we might still inquire into the cause of these, and thus 
proceed, till Ave came to the direct action of God, which 
is the ultimate efficient cause of all natural phenomena. 

In investigating what causes would produce certain 
supposed effects, we reason from intuitive principles, 
combined with our experience as to what causes pro- 
duced precisely similar effects ; and the course of pro- 
ceeding is essentially the same as that just discussed. 
We argue on the principle that a cause which has pro- 
duced a certain effect, will produce the same effect again, 
if operating in the same circumstances. 

In ascertaining the effects of known causes, the pro- 
cesses are very similar to the preceding: but they are 
generally simpler, and the aid of direct observation or 
experiment is frequently more extensive. For, as the 
agents, or others quite similar, generally operate within 
our view, we can observe the results, whereas the causes 
of many visible effects have long ceased to operate, and 
therefore observation may be unavailing. Sometimes, 
again, a single well-conducted experiment is conclusive, 
as an agent will always produce what it has once pro- 
duced, in the same circumstances, while the fact that a 
certain agent produces effects precisely similar to the one 
in question, does not prove that this did not spring from 
an agency in some respects widely different. 

In many important cases, however, experiments are 
inadmissible or impracticable. Thus, we can rarely test 
a political theory, by starting a community organized on 
its principles ; and we cannot, without imminent danger 
of sacrificing life, try the influence of powerful newly dis- 
covered medicines, by administering them experimental- 
ly. In all such cases, we must have recourse to the more 
indirect methods already explained, the rules for testing 
effects being substantially the same as those by which 
we ascertain causes. 

Where the causes in question have ceased to act, we 
may observe the effects of perfectly similar causes which 
still operate ; and, if none such exist, we must extend our 
observation, and apply such of the preceding rules as are 
applicable to the nature and circumstances of the case. 

The fact that similar causes generally produce similar 
effects, often aids us in determining the effect of a cause 
similar to one whose effects are already known. But 
the same caution is requisite here as in the case of the 



Sec. 3.] Tracing Effects. 181 

converse principle stated above : for there are numerous 
exceptions. Thus, not only do different degrees of heat 
sometimes produce very different effects, but those of a 
freezing cold strongly resemble a burn. 

Where an agent produces several distinct effects, inde- 
pendent of each other, every one of them may be studied 
as if it were the sole effect, without any reference to the 
others : and this course is frequently requisite, in order 
to avoid confusion, and to obtain a correct and extensive 
knowledge of the particular phenomenon under consider- 
ation. 

In many instances, the various effects are directly con- 
nected with each other, and re-act on their causes, as in 
cases of many moral and political agencies. Here it is 
requisite to take a wide view of the subject, in order to 
obtain a just and adequate knowledge of it. We should 
first acquire an accurate knowledge of all the phenome- 
na, considered simply as such, and then apply the proper 
principles, in order to discover their mutual relations and 
connections. We must not infer that the same cause 
which produces an effect in one case, may not be the re- 
sult of this effect in another. Penury sometimes pro- 
duces vice ; but vice more frequently produces penury. 
Wherever we can discover a primary cause, we should 
first ascertain its original effect, then trace the reciprocal 
influence exerted on it by this effect, and afterwards in- 
quire how the latter is re-affected by what it has itself 
produced. 

In all inquiries regarding causes and effects, we should 
ascertain the real character of the thing which we as- 
sume as known : else we shall either fall into error or 
lose our labor. Thus, if we assume that a bad law is 
good, and then try to trace its effects, we shall undoubt- 
edly arrive at an erroneous conclusion ; or if we attempt 
to discover why nature abhors a vacuum, or why swal- 
lows can live under water during winter, we shall cer- 
tainly labor in vain, because our assumptions are false. 
Effects which never existed can have no causes; and im- 
aginary causes can produce no efi'ects. 

So we should note and bear in mind the particular ob- 
ject of our investigation, and not confound an inquiry 
into causes with one into effects, or one into the imme- 
diate with one into the ultimate cause. 



182 Language. [Chap. XL 



CHAPTER XL 

OF LANGUAGE. 

§ 1 . Origin and Progress of Language. — Causes of Language. — 
Its two primary Sources. — Its further Progress. — Formation of va- 
rious Parts of Speech. — Modes of enlarging the stock of Words. — 
Foreign and vernacular Roots. — Origin of different Significations 
of the same Words. — Apparent and real Derivatives. — Origin of 
the Diversity of Languages. — Language not of Divine Formation. 
— Importance of knowing its Origin. 

Man is very superior to all the lower animals in the 
power of vocal expression, while he surpasses them still 
more in the extent and vigor of his thinking faculties. 
These appear to be the causes that have raised, on a 
very narrow foundation, a system of phonetic expression 
which, even among the rudest of the human race, incom- 
parably excels anything found among the lower creation. 
If we compare the highest attainments of a parrot with 
what a child effects by his own unaided efforts, we shall 
have a striking proof of man's superiority : and if we 
further notice the ingenuity with which the dumb com- 
municate their thoughts to each other, without any train- 
ing, we shall readily understand the manner in which 
spoken language must have originated, and infer that it 
is a natural result of our circumstances and faculties. 

Man expressed all his strong emotions and desires by 
peculiar instinctive ejaculations, and also imitated the 
various sounds that he heai'd. From these two sources 
have sprung all spoken language. When we examine 
even the most copious original language, such as the An- 
cient Greek, we easily trace its myriads of words to a few 
hundred roots, which give manifest indications of their 
origin. Such words as eat, laugh, moan, groan, hiss, 
buzz, hum, crash, crush, rush, croxo, roar, lore, snarl, hurl, 
gurgle, murmur, purl, coo, cackle, snap, slap, rap, cut, 
babble, hop, strike, bull, bee, drum, horse, cuckoo, &c, &c, 
evidently originated in onomatopoeia, or an imitation of 
natural sounds. Most actions are accompanied by cer- 
tain sounds, an imitation of which would form the verbs 



Sec. 1.] Its Origin and Progress. 183' 

employed to signify them. So the original names of an- 
imals would consist either of an imitation of their own 
cries or of the instinctive exclamations uttered on first 
beholding them. 

It will not admit of a doubt that man Avould soon dis- 
cover his extensive powers of vocal expression ; and the 
rapidity and precision with which he could thus com- 
municate his thoughts could not long escape his atten- 
tion. This would lead to the constant use of those 
sounds, by the head of the family, to denote the objects 
and actions which they were employed to express in the 
first instance ; and the other members of the household 
would, of course, adopt his expressions. Proper nouns, 
or names originally applied to individual objects, would 
be generalized by being applied to all things of the same 
kind, just as children call every horse or ox by the names 
of their fathers'. 

Language being thus started, it would gradually be 
extended and improved, in various ways. At first it 
would be much assisted by gestures and expressions of 
the countenance : but as it became more copious, these 
would fall into disuse, except to give it force and vivac- 
ity. 

The same words would be frequently used to denote 
both objects and actions ; or, in the language of gram- 
marians, they would be employed both as nouns and as 
verbs, a practice of which we have still many instances, 
as feed, drink, touch, feel, smell, taste, love, hate, hope, 
fear, earth, air, fire, water, and light. Which was the 
earlier use is a question of little consequence. Many 
words were probably used in both significations from 
the first, while in some cases the verbal sense probably 
had precedence, and in others the nominal. 

Adjectives arose from using participles or the names 
of actions and objects to denote qualities, a practice still 
common. Thus, we speak of a " straight" (that is stretch- 
ed) line, a " brick" house, a " sea" bird, " iron" strength, 
and so forth. In many instances, the form of the word 
was changed, to correspond with the different significa- 
tions, the older being generally retained for the quality. 
Thus a " red" color is a " roe" color, and " ten" men is 
" toes" men, as we shall readily see by referring to the 
corresponding German and Saxon terms. In other cases, 
the original meaning was entirely lost ; and it now ap- 



184 Language. [Chap. XL 

pears as a noun or a verb only in some kindred language. 
Thus, we have the origin of " stro?)g" in the Latin string, 
stretch or strain ; and the source of toeak is found in 
vine (past vie), subdue or overcome. So we find the or- 
igin of green in the Latin gramen, grass. 

Interjections are a part of instinctive language, and 
must, therefore, have been nearly as numerous in the ear- 
liest times as they are now. 

Adverbs were originally phrases, adjectives or parti- 
ciples, of which they still exhibit many indications. Thus 
to-day is simply this day, as the corresponding Latin ho- 
die is only hoc die (this day). The same remark applies 
to prepositions and conjunctions, although several of 
these were originally pure verbs, as some of them are 
still, such as except and suppose. 

The advantages of distinguishing the speaker and the 
person addressed or spoken of, are so great and obvious 
that the personal pronouns must be nearly as old as the 
first origin of language. Yet they probably sprung from 
nouns, participles and adjectives, as we may infer from 
the abridgements which they have undergone, since the 
period of the earliest written compositions. 

In enlarging the stock of words otherwise than by the 
original processes, arbitrary terms, entirely new, were 
rarely introduced, since they would sound strange, and 
furnish no key to their own signification. Instead of 
this, other methods were adopted. Old words were 
gradually changed in pronunciation, till several sprung 
from one; and the different forms which thus arose, 
were used to designate different modifications of the 
same thing, each form being appropriated to what it was 
thought to express with most precision. Thus, a child 
squalls, and a pig squeals / an owl screeches; a person 
suddenly frightened shrieks ; and a woman in great pain 
screams. In some cases, instead of changing the old 
word directly, it was adopted from another language, in 
its altered form, with a new but kindred signification. 
Thus, the winds blow, and the waters floio. The latter 
word is directly from the Latin ; but it sprung from the 
same root as the former. So aur-ist is only a Greeco- 
Latin form of ear doctor. 

A more fertile source of additions, at least in the more 
cultivated languages, was the practice, still common, of 
uniting two or more, to form one word. Here the new 



Sec. 1.] Its Origin and Pkogkess. 185 

meaning is a modification of the thing denoted by the 
principal compounding term, which is particularly indi- 
cated by the other word. Thus, in the word bookseller? 
the last syllable is the principal root, or that which de- 
notes the object meant. Er is an abridgement of the 
old word wer, a man, so that sell-er is, a man who sells, 
and book-sell-er, a man who sells books. 

The compounding terms, instead of being adopted 
from the vernacular, were often taken from some for- 
eign language. This frequently rendered the meaning 
of the compound much more definite, especially in ab- 
stract terms, or such as express a great variety of things. 
For, as the compounding terms were unfamiliar, the act- 
ual signification of the compound depended mainly on. 
the definition, and therefore its exact import was not 
readily mistaken, so that a word formed in this way was 
equivalent to the invention of an entirely new term. 
Compounds formed from vernacular words, on the other 
hand, directly suggest a meaning, independently of any 
definition, which is often considered unnecessary, in such 
cases. But the literal signification of the compounding 
words is frequently different from the true one, especial- 
ly in technical and scientific terms ; and hence will arise 
obscurity and error, unless we attend to the actual, and 
not to the etymological sense. 

To illustrate this difficulty, we may observe that Ge- 
ometry literally signifies land-measuring, Geography, a 
description of the Earth, and Geology, a discourse about 
the Earth, so that, if we look only to the etymologies, * 
we should be quite misled regarding the first, and we 
could not distinguish the second from the third. So 
Astrology, etymologically considered, is a more proper 
term for what is called Astronomy, as the former liter- 
ally signifies the science of the heavenly bodies, and the 
latter, only the science of their laws. Alchemy and 
Chemistry are only different forms of the same word ; 
yet their real meanings differ as much as those of the 
two preceding terms. 

Owing to the difficulty and inconvenience of forming 
new terms, various significations were frequently attach- 
ed to the primary import of many words, without their 
undergoing any change. A common instance of this 
was, employing words which originally meant physical 
objects to denote impalpable things, to which they were 



186 Language. [Chap. XL 

believed to bear some analogy. Thus, the same Hebrew 
word denotes both wind and spirit ; and the Latin ani- 
mus, mind, and anima, soul, are evidently identical with 
the Greek anemos, wind. So investigate originally meant 
to track, and ponder, to weigh. As objects of sense first 
received names, because they first excited attention, those 
of all others originated chiefly in this manner, although 
the primary significations are now found, in many in- 
stances, only in other languages. 

Words and expressions were frequently employed fig- 
uratively, to denote things which bore some real or fan- 
cied resemblance or relation to the original significations, 
and, in many instances, this usage prevailed so extensive- 
ly that the new meanings became as familiar as the pri- 
mary, so that the original metaphor disappeared. Thus 
a "hard-hearted" man is not considered a figurative ex- 
pression, any more than a hard rock. 

Sometimes the new significations entirely superseded 
the originals ; and, not unfrequently, a third was ingraft- 
ed on the former, which bore no resemblance to the lat- 
ter. Thus, the word virtue originally signified manli- 
ness, being taken from vir, a man — then, bravery, because 
that is a manly quality — and, finally, any good quality, 
so that we speak of the virtues of drugs and plants. By 
this means the same word sometimes came to have con- 
trary significations. The Latin sacer means both holy 
and accursed, the original signification being set apart or 
separated. 

When the vocabulary of a language had thus become 
comparatively copious, figurative expressions became less 
common ; and the general style became more precise and 
literal, because there was less occasion for metaphors, 
while the more extensive application of language for di- 
dactic purposes rendered perspicuity and precision more 
desirable. 

Words not primitive are usually divided into com- 
pound and derivative: but there is generally no real 
etymological difference; for most derivatives are only 
compounds of which the subordinate compounding terms 
no longer appear separately in the language. These are 
generally found, however, either in its older forms or in 
other languages. Thus the affix er is the Saxon wer, a 
man, so that hunter is, in reality, a compound as much 
as huntsman / and the common prefix in or un, signify- 






Sec. 1.] Its Origin and Progress. 187 

ing not, occurs in Hebrew as a distinct Avord, with the 
same sense. 

Sometimes prefixes and affixes are only common terms 
slightly altered. Begird is by-gird or gird round ; mis- 
pronounce is miss-pronounce y and manly is man-like. 

The real derivatives of a language are, the various new 
forms of a word, employed to denote several modifica- 
tions of the same thing : but as it is difficult to ti'ace the 
derivation, in such cases, grammarians have frequently 
considered all the forms primitive words. 

Different communities pronounced, compounded, and 
contracted words variously, and employed different new 
terms to denote the same thing, while each, in many in- 
stances, superinduced peculiar new meanings on the pri- 
mary. Striking differences arose, also, from some races 
amalgamating modifying words with the principal terms 
in pronunciation, such as personal pronouns with the 
verbs of which they were nominatives, and personal pro- 
nouns and prepositions with the nouns which they qual- 
ified. Hence originated numerous inflections, as in Latin 
and Greek, while other races, as the Chinese, always kept 
the words distinct, whence their languages exhibit hard- 
ly any inflections. Other differences arose from figura- 
tive or poetical expressions superseding, in some lan- 
guages, the original terms which others retained. 

When we further consider the wide diversity in the 
circumstances of communities, and in the objects with 
which they were conversant, the great variety of lan- 
guages which is found throughout the world, appears 
only a natural consequence of these numerous caiises of 
divergence. If we observe the rapidity with which a 
copious language has run into several, within the period 
of authentic history, we can easily understand how quick- 
ly a language, yet rude and barren, might run into many, 
while the art of writing was unknown, and communities 
were very small. A patriarch, living alone with his fam- 
ily, would communicate to them his own linguistic pe- 
culiarities ; and these would increase, more or less, with 
every successive generation, more especially if every one 
of the sons separated from the common parent, and held 
little further intercourse with his kindred, as would very 
frequently happen in early ages when the greatest part 
of the world was yet uninhabited. It may further be 
observed that the names of things which vanished from 



1 5 S Language. [Chap. XL 

sight would be forgotten, "while new terms would be 
used to denote new objects. 

"When a language has become copious, assumed a 
definite form, and been reduced to writing, subsequent 
changes of the old elements and constructions may be 
very slow, although it may receive a host of new words. 
Hence those languages which sprung from a common 
source, at periods long subsequent to the general dis- 
persion of mankind, frequently resemble each other very 
closely, while those which separated much earlier often 
retain such faint traces of their original unity that this is 
established only by means of the intermediate languages, 
which serve as connecting links. 

"We are told, in the Holy Scriptures,* that God brought 
the animals to Adam, in order that he might name them, 
and that whatever Adam called every species became its 
name. Xow animals would excite attention before any 
other object ; and when language had once originated 
by giving them names, there was no occasion for miracu- 
lous aid to continue the process thus begun. The mea- 
ger foundations on which language is built, the numer- 
ous and palpable marks of onomatopoeia which it still 
displays, the absence of terms originally denoting any 
mental or immaterial objects, and the many defects with 
which it abounds, and which are particularly observable 
in its most ancient forms, show that it is of human, and 
not of Divine, origin. 

The Almighty would not encourage mental inactivity 
by conferring miraculously what he gave us faculties for 
forming in a natural way. Xor is it credible that he 
would act thus when the gift was soon to be lost irre- 
coverably, and superseded by a multitude of rude lan- 
guages, precisely such as mankind would readily have in- 
vented, without any miraculous aid. 

A correct view of the origin and progress of language 
is requisite, in order that we may use it aright ourselves, 
and properly interpret the expressions of others : for er- 
rors on this subject produce fallacious rules both of in- 
terpretation and of composition. The fiction of the Di- 
vine origin, and consequently primitive perfection, of lan- 
guage, repels scrutiny, misleads the grammarian, and 
tends strongly to produce and foster the common error 
that language is a correct representation of nature, and 
* Genesis, Chapter ii., verses 19 and 20. 






Sec. 2.] Its Uses. 1 89 

that we can discover truth by the study of mere expres- 
sions. 

§2. Uses of Language. — Uses and Defects of "natural" Lan- 
guage. — Original object and superiority of Speech. — Its other Ad- 
vantages. — Use of General Terms. — Eequisites to the proper ex- 
pression of Thought. — First Rule. — Common Violation of it. — 
Different styles of didactic and emotional compositions. — Compre- 
hension and Extension of Terms. — Second Rule. — Sources of Am- 
biguity. — Third Rule. — Common Errors. — Means of testing the 
amount of our Knowledge of a subject, and of avoiding Vagueness 
and Obscurity of Expression. — Verbal and Real Definitions. — Why 
the former only belong to Logic. — Three Rules regarding them, 
with Remarks. — General characteristics of good Definitions. — 
When new Terms may be rightly employed. — Ordinary Practice. — 
Foreign and Vernacular Roots. — Evils of introducing new Terms 
unnecessarily. — Origin of many new Terms. 

Gestures, expressions of the countenance, and instinct- 
ive exclamations, which have been termed " natural" lan- 
guage, bear the same relation to speech that pictures do 
to phonetic writing ; and hence they are very service- 
able in exciting the passions. But they are incapable of 
expressing many thoughts at all, and others they express 
only vaguely, while their power of exciting emotion is 
positively unfavorable to them, as a means of communi- 
cating knowledge, since disturbing emotions are fertile 
sources of error. 

The original object of speech was, simply to express 
or communicate thought: and vocal language possesses 
over every other means the advantages of much greater 
precision and rapidity of communication. Even if we 
could invent manual or other inaudible signs, to denote 
every thought, there are none that could be communi- 
cated so rapidly as vocal signs or words. Nor could 
man have invented such signs without the previous as- 
sistance of words, as otherwise many of the requisite 
signs could not be agreed on. 

It is by means of words alone that the attainments of 
one person or generation can be satisfactorily communi- 
cated to another, and mankind be both benefited by the 
experience or labors of their predecessors or contempo- 
raries, and enabled to add to their acquisitions. 

Speech is also employed, in a written form, to aid us 
both in our oi'iginal researches and in retaining our ac- 
quisitions. For we cannot generally follow out a long 
and intricate train of reasoning, without assisting the 



190 Language. [Chap. XI. 

Memory by written symbols, which could never have 
been brought to any degree of perfection without the pre- 
vious use of words. But, by means of written speech, 
we can clearly express every step of the most intricate 
and subtle process ; and thus we can easily retrace our 
steps, whenever we wish either to recall something which 
we have forgotten, or to test the accuracy of certain prop- 
ositions, by a deliberate examination of the various proc- 
esses through which they have been professedly estab- 
lished, so that none of them may be overlooked. 

The aid of language is requisite to retain even a frag- 
ment of our former acquisitions, in such a manner that 
we are safe from error : for we are liable to forget our 
former conclusions, as well as the processes by which we 
arrived at them, so that we readily mistake them for 
others which they resemble, and thus confound what we 
established with what we only heard, read, or imagined. 

Language greatly aids reasoning and remembrance, by 
means of comprehensive and general terms. Even such 
simple expressions as ho%)e and fear imply things which 
the Memory could not easily retain, without the aid of 
language, and much more will this remark apply to such 
terms as duty, law, and government, which distinguish 
the things denoted by them from others with which they 
would be confounded, but for the aid of expressions 
showing the very things meant. Such terms are also 
requisite in the higher kinds of generalization, that we 
may be able to remember and reason regarding preced- 
ing results : and they also enable us to reason upon as- 
sumptions regarding things of which we can have no 
idea, such as indefinitely small quantities, or even things 
which cannot exist, as the square roots of negative quan- 
tities. 

In order to express our thoughts aright, we must pos- 
sess a knowledge both of the subject and of the language 
we employ : and when these prerequisites have been ac- 
quired, the observance of the three following rules will 
secure proper expression. 

1. We should say precisely what ice mean. It is not 
sufficient to avoid expressions totally wide of our mean- 
ing : we must beware of saying either more or less than 
we intend. Terms may be either too general, and thus in- 
clude something which ought to be omitted; or they may 
be too particular, and consequently omit something which 



Sec. 2.] Rules op Expression. 191 

ought to be included. In mere illustrations, and in com- 
positions designed to excite emotion, it is often proper 
to employ terms more particular than truth would war- 
rant : but in purely scientific or didactic discourse, this 
should be avoided, because the more general expressions 
are the more extensive and concise. 

Particular terms express more qualities of the thing 
meant ; and hence their superiority for emotional and il- 
lustrative purposes. " Horse" expresses more qualities 
than " quadruped," and the latter, many more than " ani- 
mal." The more species a term embraces, the fewer 
qualities it denotes, and conversely. The number of 
qualities a word expresses is termed its comprehension, 
and the number of individuals or species that it indicates, 
its extension. These two evidently vary inversely ; the 
wider the one, the narrower the other. 

2. Our expressions should not be ambiguous. We 
should reject expressions which admit of two or more 
significations, without violating any just rule of interpre- 
tation. Expressions are ambiguous, either where one or 
more of the terms beai'S several significations, and the 
context does not determine which is intended, or where 
a phrase is susceptible of various grammatical construc- 
tions. 

3. Our expressions should be perspicuous. In order to 
this, we must avoid those expressions of which the exact 
signification cannot be detected without difficulty. We 
are liable to employ words of whose signification we 
have no clear notion, without ever being aware of our 
doing so, because they are familiar to our ears ; and thus 
we are apt to overestimate our knowledge of the sub- 
ject. One of the best means of testing the amount of 
this is, to write down what we know, in terms which are 
perfectly clear and unambiguous, and which will give 
any person of ordinary perspicacity a correct notion of 
what is meant. The application of this test will show 
that we are apt to mistake a familiarity with words for 
a knowledge of what they denote, two things widely dif- 
ferent. 

In order to secure perspicuity, we must not employ an 
expression without knowing precisely what we under- 
stand by it ; and when we are obliged to use one that is 
obscure, ambiguous or not well known, we should clear- 
ly fix the sense in which we employ it, either by the form 
of the expression or by a definition. 



192 Language. [Chap. XI. 

Definitions are either verbal or real. The former point 
out what terms denote certain things, which they assume 
that we know ; the latter unfold the nature of the things 
denoted by certain terms. If we are told that " blue is, 
the color of the sky," this is a verbal definition, and 
teaches nothing unless we know what the color of the 
sky is. But if we are told that " a dial is an instrument 
for measuring time, by means of the different directions 
in which a shadow falls, throughout the day ; and it con- 
sists of a flat surface, marked with the hours, and a 
style or axis, for projecting the shadow" — this is a real 
definition, which would give us a notion of what a dial 
is, if we had never seen or heard of such a thing before. 

Definitions written for our own use exclusively will be 
verbal, since they are designed merely to aid us in re- 
membering the meaning of words, or the sense we at- 
tach to them. We cannot give a real definition of a 
thing of which we are ignorant : and when we know the 
thing, the object of a definition for our own use can only 
be, to remind, us of the term by which it is designated. 
Hence the subject of real definitions belongs to Educa- 
tion or Rhetoric, and not to Logic. 

The following are the principal rules regarding verbal 
definitions. 

1. The definition should be free from the difficulties 
which it is designed to obviate or remove, and accord 
with the rules of correct ex]y>'essio?i. If it is inaccurate, 
ambiguous, obscure, or couched in terms partly unknown, 
it is worse than useless, since it misleads, while it pro- 
fesses to guide. A common violation of this rule is, to 
employ defining terms which are as unintelligible as the 
word defined, so that the definition is tantamount to say- 
ing a thing is what it is. Thus, life has been defined " a 
system of vital forces," that is — "a system of forces per- 
taining to life." So, justice is defined, in the Institutes 
of Justinian, " a constant and perpetual desire to give 
every one his right," which is equivalent to saying that 
"justice is, a desire to do justice to every one," since a 
man's right requires to be defined as much as his just 
due. 

2. The thing defined should be clearly pointed out, and 
distinguished from all others. In order to this, the defi- 
nition must express the peculiar characteristic of the 
thing defined, and exclude that of every other being. 



Sec. 2.j Definitions. 193 

Consequently every negative definition violates the first 
part of this rule, since it never tells us what a thing is, 
hut only what it is not ; and every definition which ap- 
plies equally to other things, violates the second part of 
the rule. It is not a proper definition of a man, to say 
that " he is not a fish," as this includes every being ex- 
cept fishes, while it wholly fails to tell us what man is. 
So, the definition " man is a rational being," violates the 
rule ; for so are angels. 

3. The definition should comprise the whole of the 
thing defined, and not merely a part of it : otherwise it 
is defective. It is not a proper definition of ruminants, 
to say that " they are sheep and oxen ;" for goats, deer, 
antelopes and camels also belong to that order. Nor is 
it a proper definition of swans to say that "they are 
large, white birds, of the order natatores or swimmers ;" 
for this excludes the black swans. This rule is very apt 
to be violated wherever our views of the subject defined 
are too narrow, since our attention is apt to be confined 
to that with which we are familiar, so that we overlook 
the rest, although this may possibly be the largest and 
most important part. 

A proper definition requires both a good knowledge 
of the subject and care in forming it. Hence our defini- 
tions generally improve as our knowledge of the subject 
becomes more extensive, and further examination and ex- 
perience gradually show the imperfections of former def- 
initions. 

Many definitions can generally be given of the same 
expression ; and the best is, that which gives the most 
correct notion of its import to the party for whom it is 
intended. Hence definitions designed for our own use 
should be such as are most satisfactory to ourselves, al- 
though they might not be suitable for others. We 
should, however, depart from the ordinary signification 
of terms as little as a regard to clearness and precision 
will permit, since difficulty and error are very apt to 
arise from affixing peculiar meanings to terms. But 
when we are obliged to employ a vague term, we should 
either define or distinctly note the particular sense in 
which we employ it : otherwise obscurity or error will 
probably result. 

When there is no term in the language to denote the 
meaning, without great risk of error, the best way is, to 



194 Language. [Chap. XI. 

adopt a new word. This is generally desirable where a 
new name is required for something essentially different 
from anything which already has a name in the language : 
for, to attach the new meaning to some old term would 
lead to confounding the various significations, a thing 
which has been a fertile source of error. 

Sometimes it is requisite only to borrow a word from 
a foreign language, and modify its form, if necessary. 
In other cases, we must coin a new term. It has been a 
common practice to form a conrpound from Latin or 
Greek roots, adhering to the proper rules of composition 
or derivation. The latter language is generally prefera- 
ble, because it is more unlike the vernacular. Where the 
thing can be expressed exactly by vernacular roots, these 
should be adopted in preference, since the compounding 
terms directly suggest the signification of the word. 
Compounds of this kind are generally better for emotion- 
al purposes, as they affect the feelings more strongly : 
but they are frequently objectionable for didactic pur- 
poses, as they tend to mislead us regarding their exact 
signification. 

The use of new words should be avoided, when there 
is no urgent occasion for them, since their introduction, 
in such cases, only clogs a language, like useless wheels 
in a machine. It also fosters error, owing to the com- 
mon tendency to assume that different words must de- 
note different things. Many new terms have sprung 
from pedantry, ignorance, or an affectation of originality, 
superior discernment, and refined feelings, which had no 
real existence. 

§ 3. Imperfections and Abuses of Language. — Origin of the Im- 
perfections of Language. — (1) Idioms. — (2) Different admissible 
Constructions. — (3) Different Significations of Words. — (4) Terms 
expressing Nonentities. — (5) Deficiency of Words. — (6) Terms con- 
veying false Impressions. — (7) Superfluous Words. — Pernicious Er- 
ror. — Requisite in order to a right understanding of Terms. — Ori- 
gin of abuses of Language. — (1) Using vague and obscure Words. 
— Common Instance. — Sources of this Abuse. — Means of guarding 
against it. — (2) Confounding different Significations. — How to be 
avoided. — (3) Conveying erroneous Meanings. — Instances. — How 
to be avoided. — Combination of Abuses. 

Language represents, not the realities of nature, but 
the opinions of those who formed it ; and as these were 
often erroneous, language exhibits corresponding imper- 
fections, of which the following are the principal : 



Sec. 3.] Its Imperfections. 195 

1. Language abounds with idioms, or peculiar phrases, 
the precise significations of which are not indicated by 
the terms composing them, but must be learned from ob- 
serving the occasions on which they are used. Conse- 
quently they are very liable to be misunderstood by those 
who are not well acquainted with the language. These, 
again, may mislead others, by employing or defining 
those terms improperly. 

2. Many expressions admit of various constructions, 
every one of which gives a different sense, while it may 
be difficult to ascertain the true construction; and con- 
sequently it is often missed. 

3. Owing to the new significations superinduced on 
the primary, many icords denote things widely different, 
some of which are readily mistaken for others, because 
the different significations are often connected in sense, 
and always, by the bond of the common name. 

4. Many expressions denote things which have no ex- 
istence. Such are satyr, dryad, fairy, mermaid, sylph, 
griffin, empyrean, and primum mobile. As the names 
exist, we are apt to think that they denote correspond- 
ing realities, which, however, are wholly imaginary. 

5. No word exists for many things which ought to be 
distinguished by a pemliar term. Hence it becomes nec- 
essary, either to affix new significations to old words, or 
to introduce new terms, in order to denote such things ; 
and this produces changes which render language either 
more vague or less intelligible. 

6. Terms have been invented to express things regard- 
ing which vague or erroneous opinions prevailed at the 
time of their formation, so that they convey false impres- 
sions regarding the reality. Such are animal spirits, 
humor, sensible species, and vitality. Terms of this kind 
had no clear and correct signification originally; and sub- 
sequent alterations sometimes made matters still worse. 

7. Language contains many words so nearly resem- 
bling each other in signification that one or more of them 
might be discarded to advantage. Such are perhaps, per- 
adventure and perchance — among, amo?igst, amid and 
amidst — nitrogen and azote — and beticeen and betwixt. 
Not only are slight modifications of the same thing oft- 
en denoted by totally different terms, but the very same 
thing sometimes has several names ; and hence we are 
apt to think that the things meant must be as distinct as 



196 Language. [Chap. XI. 

the words by which they are expressed. Wherever any 
of these modifications do not require to be frequently 
mentioned in discourse, as distinct from its class, the 
proper plan would be, to denote it by the general term, 
with some ejDithet indicative of its peculiarity, and to 
drop the special term altogether. This would render lan- 
guage more intelligible, precise, and easier of acquisition. 

To overlook the preceding imperfections, and assume 
that language gives a faithful and intelligible represent- 
ation of nature, is an ancient and still prevalent error, 
which has produced many fallacies. Some believe that 
there are fairies because we have a name for them ; and 
most of the ancient astronomers never suspected that their 
" crystalline spheres" were wholly imaginaiy. Hence, 
also, has arisen the erroneous opinion that a knowledge 
of nature can be communicated by means of words alone, 
whereas we cannot be instructed by words which we do 
not understand, and the signification of a term can never 
be understood, unless we learn, by our own original com- 
prehension, the primary elements of the thing which it 
denotes, just as no definition can give the blind a correct 
notion of color. 

Owing to the fallible nature of our faculties, and their 
being often swayed by prejudices or bad motives, we 
are liable to use language improperly, even if it were 
perfect, while these abuses are increased by its imperfec- 
tions. The most common of those abuses may be re- 
ferred to one or other of the following heads : 

1. Language is used so vaguely or obscurely that it is 
very difficult to ascertain the sense, or tchether any defi- 
nite sense is conveyed. A common instance of this abuse 
is, where figurative expressions are employed, so that we 
either cannot know what is meant, or we are unable to 
determine whether the expression is figurative or literal. 
When compositions which abound with this defect are 
carefully analysed, it will generally be found that the 
author had neither a clear conception of his own mean- 
ing, nor a good knowledge of his subject. 

This abuse is of common occurrence, and frequently 
very pernicious in its consequences. It springs chiefly 
from ignorance, carelessness, an affectation of originality, 
learning or depth, and dishonest intentions. 

A man cannot express himself clearly and accurately, 
in his own words, on a subject which he does not under- 



Sec. 3.] Its Abuses. 197 

stand : and this appears to be the source of much of the 
obscurity and darkness which characterizes many treat- 
ises and compositions on mental science; for the lan- 
guage is frequently erroneous, whichever way it may be 
interpreted. But as the subjects of investigation are im- 
perceptible to the senses, these faults are apt to escape 
the reader or hearer's attention ; and he may thus admit 
as self-evident or fairly proved, a proposition really ab- 
surd, or incapable of valid proof. 

It is easy to assume that everything is correct, where 
there is nothing manifestly false, while it is sometimes 
difficult to detect the true character of profound jargon 
or sublime twaddle ; and hence these have often passed 
for being what they appear. It requires no severe think- 
ing to employ such language, while it procures the ad- 
miration of those who believe that the depth of a dis- 
course must be proportional to its darkness, and -that 
what they readily and cleai'ly understand, must be com- 
paratively superficial, whereas the case is very frequently 
the exact reverse. This leads the shallow-minded and 
dishonest to use foggy, recondite and high-sounding ex- 
pressions, when clear and ordinary terms would be much 
more appropriate. 

Carelessness frequently leads to similar results. If a 
person is hurried, and inattentive to his words, he will 
often use terms which convey no clear or definite mean- 
ing to the party addressed, although his own views of 
the subject should be both accurate and profound. This 
is particularly apt to occur where he has paid little at- 
tention to the proper expressions for denoting his mean- 
ing. 

A common temptation to indulge in this kind of com- 
position is, the air of originality, profundity, and import- 
ance, which trite or puerile thoughts assume, in the eyes 
of many, when they are clothed in a new, vague, and 
pompous phraseology. 

Another frequent source of this abuse of language is, a 
desire to mislead those addressed, or to shun the respons- 
ibility of telling the truth clearly, by employing obscure 
or ambiguous terms, while the speaker or writer escapes 
the chai-ge of unequivocal lying, because his expressions 
are true in one sense, although he is well aware that they 
will be understood otherwise, or at least produce errone- 
ous impressions. 



198 Language. [Chap. XI. 

Many terms denote things which have various forms, 
or are incessantly changing their import, so that -when 
used without any qualifying or distinctive epithets, it 
may be impossible to ascertain the thing meant. Such 
are wealth, capital, government, legislature, church, and 
polity. A statement which holds true of one of the 
things denoted by such terms, may be quite false of an- 
other. 

A careful attention to what is actually said, will enable 
us to estimate expressions at their true value, and pre- 
vent lis from overvaluing puerility or absurdity, because 
they may be clothed in a novel or philosophic garb ; and 
we shall learn that vague, obscure, and grandiloquent 
language generally covers error or inanity. 

2. The same expressions are employed in various sig- 
nifications, which are not distinguished, so that we mis- 
take one for another. The author uses the same words 
now in one sense, and then in another, while he gives no 
clear indication of the difference : but we are required, 
or at least expected, to assume that they are used in the 
same sense throughout. This abuse is of frequent occur- 
rence, because it is very liable to escape the notice of 
both author and hearer or reader. We are so accustom- 
ed to use the same word in different senses, that the fact 
of this being done excites neither surprise nor suspicion ; 
and hence we are very apt to overlook the abuse of do- 
ing so, while the argument, or object in hand, requires 
that they should be employed throughout in precisely 
the same sense. 

To guard against this abuse, we must ascertain wheth- 
er the expressions, while professing to mean only one 
thing, are not, in reality, employed to denote several 
things essentially different. This is done by ascertain- 
ing the precise sense in which the terms are employed, 
wherever they occur. In our own case, we must closely 
question ourselves regarding our meaning, ascertain 
whether we know the precise thing that we intend to 
express, and adhere to the rules of proper expression. 
In the case of others, we must also apply the proper 
rules of interpretation. 

3. Language is employed which conveys a clear and 
definite, but erroneous, signification : and this may be done 
unconsciously, through ignorance and heedlessness, or 
wilfully, from some evil design. A common form of this 



Sec. 3.] Its Abuses. 199 

abuse is, to employ one term for another which it some- 
what resembles in sense, while their proper significations 
are very different. Thus the words impossible, incon- 
ceivable, incomprehensible, and highly improbable, which 
properly denote four things essentially different, have oft- 
en been employed indiscriminately, as if they all express- 
ed the same thing. 

Another common modification of this abuse is, errone- 
ous definition. Thus, several of our older English lexi- 
cographers tell us that the share or sock of a plough is 
the coulter or knife, which is like saying that the hand is 
the foot. So the Hebrew, Greek and Latin term for cop- 
per is generally defined, in the dictionaries of these lan- 
guages, by brass, an alloy which appears to have been 
wholly unknown to the ancients. This error is very apt 
to escape detection, because those who consult the defi- 
nition are generally ignorant of the real import of the 
word. We should never rely on the definitions of per- 
sons who are not well informed regarding the thing de- 
fined, but either apply to a proper authority, or endeavor 
to acquire some knowledge of the thing defined, and 
then compare the reality with the definition. 

A third common case of this abuse is, exaggeration 
and extenuation. On the one hand grandiloquent or hy- 
perbolical language is applied to things which do not 
properly admit of it : and on the other hand, terms ex- 
pressive of contempt are either overstrained or wholly 
misapplied. This course sometimes produces the desired 
effect, especially where it tallies with the prejudices of 
the party addressed. In other cases, the result is often 
the very reverse. Instead of being elevated, the lan- 
guage is only tumid or bombastic, in the one case : and 
compassion for its objects, with indignation against those 
who employ it, are the effects in the other. 

This abuse is to be detected by ascertaining the char- 
acter and circumstances of the author, and applying the 
proper criterions of testimony. 

Not unfrequently two or three of the preceding abuses 
are combined, as where vague terms are employed to 
convey an erroneous meaning, while the same terms are 
improperly used in various senses. Here we should first 
try to ascertain what is said, and, if we succeed in this, 
endeavor to learn its character afterwards. If we fail in 
the former object, the second, of course, becomes imprac- 
ticable. 



200 Language. [Chap. XL 

§ 4. Interpretation of Language. — Use and foundation of Rules 
of Interpretation. — Five classes of Expressions. — Three which re- 
quire interpretation. — (1) Usual Meanings to be generally adopted. 
— On what this rule is based. — Principal Exceptions. — On what 
ground these are admitted. — (2) When Figurative Meanings are to 
be adopted. — Mode of determining when an expression is figura- 
tive. — (3) When special or technical senses are to be adopted. — Re- 
lations and places of the Figurative and the Technical. — Means of 
discovering the latter. — (4) Rule regarding antiquated Significa- 
tions. — How these are to be ascertained. — (5) Rule regarding the 
intentional Sense. — Its Application. — Means of ascertaining this 
Sense. — (6) Cases in which the literal Signification must be adopt- 
ed, and why. — (7) Usages to be observed. — Foundations of this 
Rule. — Means of ascertaining Usages. — Interpretation of Idioms. — 
Observations on Corresponding Terms, and those which gradually 
change their Significations. — Applications of the Rule. — Various 
things to be considered.- — Caution. — Mannerism. — Influence of 
particular Pursuits and national Character. — (8) Rule where sev- 
eral meanings are admissible. — Its Foundations and Extent. — 
Means of application. — Common violation of it. — How to be avoid- 
ed. — Remarks on cases to which it is inapplicable. — Latent Am- 
biguities. — Implications. — Aids where we depend on Translations. 
— Requisites to a proper application of the Rules of Interpretation. 
— Sources and Evils of Misinterpretation. 

The difficulties which arise, in attempting to ascertain 
the precise meaning of expressions, are to be surmount- 
ed by a proper application of the rules of interpretation. 
These are founded on the structure and usages of lan- 
guage, so that their validity admits of no question, al- 
though people may differ occasionally regarding their 
applications. 

With reference to interpretation, all expressions may 
be divided into the five following classes. (10) 

1. Those of ichich the signification is tcell known, 
clear, unchangeable and unambiguous. This class in- 
cludes most of the names of natural objects, and those 
words which denote simple external actions and direct 
comprehensions, such as Sun, Moon, shy, tree, man, hand, 
foot, black, white, hot, cold, go, come, sit, eat, drink, see, 
hear, &c. To all who possess an ordinary knowledge of 
the language, words of this kind require no interpreta- 
tion ; and it is chiefly by their aid that we can rightly 
interpret others. 

2. Those which convey no reed meaning. Here inter- 
pretation is needless, as it would be folly to search for a 
meaning where none exists. 

3. Those which are ambiguous, or which admit of sev- 
eral interpretations. 



Sec. 4.] Interpretation. 201 

4. Those which are obscure, or in which we cannot 
readily discover any certain meaning. 

5. Those of lohich the meaning is wholly unknown, 
such as obsolete and unusual words, and foreign terms 
of which we have not yet, in any degree, ascertained the 
significations. 

Thus we see that the ambiguous, the obscure, and the 
unknown comprise the whole field of interpretation : and 
the following are the principal rules for removing the 
difficulties which they occasion : 

1. The literal or ordinary signification of words is al- 
ways to be adopted, except ichere there is some urgent rea- 
son for departing from it. This rule is founded on the 
fact that the literal is the common or usual signification, 
to which all others are only exceptions. 

The following -are the principal cases in which we 
ought to depart from the literal signification : (1) Where 
it renders the expression absurd, or gives it a meaning 
which cannot possibly be true. (2) Where it gives either 
a puerility or no meaning at all. (3) Where it gives the 
passage a meaning at variance with known truth, the 
whole scope and tenor of the discourse, or the vieios and 
opinions of the author. 

These exceptions to the general rule are admitted on 
the grounds that figurative and special meanings of words 
are common, that persons do not generally speak mani- 
fest absurdities and puerilities, that their expressions usu- 
ally have a meaning, that they sometimes employ words 
which convey a sense different from what they intended, 
and that they seldom utter glaring falsehoods, or direct- 
ly contradict themselves. 

In all those exceptional cases, we must search for some 
other sense than the literal; and of this kind the figura- 
tive, the special or technical, the- antiquated and the in- 
tentional, are the most common. 

2. A figurative rendering is to be adopted where it is 
admissible, and gives a good sense, which the literal does 
not give. The various kinds of figures, and the circum- 
stances under which they are employed, are so well 
known that it is generally easy to determine when a fig- 
urative meaning is to be adopted : and we are farther 
aided by the manifest difficulties attending a literal in- 
terpretation, in such cases. 

The nature of the composition often indicates whether 
T 2 



202 Language. [Chap. XL 

an expression is figurative. In poetry, rhetorical com- 
positions, and all impassioned discourse, figurative lan- 
guage abounds, while it is sparingly used in all scientific 
works, and in some it is hardly ever employed. As the 
oldest compositions mostly belong to the former class, 
they generally exhibit a free use of figurative language ; 
and they are to be interpreted accordingly. 

Those expressions which were originally figurative, but 
have entirely lost their old literal signification, are ex- 
cepted from the preceding observation ; for as the figura- 
tive has become the ordinary signification, they are prop- 
erly classed with literal expressions. 

3. The special or technical signification is to be adopt- 
ed where it is indicated by the subject or the context, and 
the ordinary signification is objectionable. By the for- 
mer terms is understood that signification which is pecul- 
iar to a certain art or science, or is employed only by a 
particular class of persons, in speaking of their distinctive 
usages, opinions, or doctrines. 

Figurative and special expressions are generally in in- 
verse proportion. The latter are extensively employed 
in purely didactic works, and very little in impassioned 
or emotional discourse. In the former, the special signi- 
fication is the rule, and the ordinary, the exception, so 
far as the subject in hand is concerned. 

The subject of discourse generally indicates the partic- 
ular meaning which we are to expect. A sailor general- 
ly uses terms in their nautical, a soldier, in their milita- 
ry, a merchant, in their commercial, and a geometrician, 
in their mathematical signification. 

The signification of the various terms is to be discov- 
ered from the oral or written testimonies of those con- 
versant with the subject to which they refer, or from 
marking their usages and formal definitions ; and much 
aid may be derived from good dictionaries of the partic- 
ular subject, where such exist. 

4. Antiquated significations are to be adopted in an- 
cient compositions, or such as treat of Antiquities. The 
general subject, or the context, points out the cases in 
which antiquated meanings are admissible ; and the prin- 
cipal thing to be avoided is, confounding the obsolete 
with the present meaning. The former may be ascer- 
tained from dictionaries which explain them, archaeolog- 
ical treatises, and an extensive acquaintance with works 



Sec. 4.] Interpretation". 203 

on the subject in question, written in the same age and 
country. 

5. The sense intended to be conveyed is to be adopted, 
though different from what the words ordinarily signify. 
Speakers or writers sometimes inadvertently omit or in- 
sert words, or employ expressions which convey a sense 
quite different from what they intended, in all of which 
cases the latter is evidently the true interpretation. 

In determining the applicability of this rule, the cir- 
cumstances of the author are to be considered. If he 
wrote or spoke deliberately, and after careful considera- 
tion, the rule is not applicable, unless the intentional 
meaning is obvious and unquestionable, and certainly 
different from the literal. In other cases, this rule may 
safely be followed, wherever the words actually employ- 
ed are such as might readily be used inadvertently, in- 
stead of those which would properly express the mean- 
ing supposed to be intended, while this harmonizes with 
the context, and the literal signification either contradicts 
it, or gives no sense at all, as when the negative particle, 
or the verb, is omitted. But the rule cannot safely be 
applied, where the supposed intended sense, though prob- 
able, cannot be clearly ascertained. 

Wherever the intentional sense differs from the literal, 
it is generally to be ascertained from the context, or the 
author's other statements ; and, not unfrequently, it is 
discovered from his acts, demeanor or circumstances. 

6. JVo meaning is to be attached to an expression, 
which it will not bear : and the ordinary signification is 
always to be adopted, where no other is admissible. The 
rules of interpretation assume that the meaning which is 
to be attached to an expression, is one which it may pos- 
sibly convey, and which is not wholly inconsistent with 
the usages of speech : for it is evidently absurd to attach 
any such meaning to words ; and, therefore, we are al- 
ways limited to admissible senses, whatever be the con- 
sequences. 

7. Expressions are to be interpreted according to the 
usages of the language, the age, the place, the subject, and 
the author. This rule is based on ttie well-known fact 
that these usages widely differ. Every language abounds 
with idioms, or expressions which have a conventional 
meaning, well understood by those who are familiar with 
it, but frequently very obscure to all others : and a simi- 



204 Language. [Chap. XI. 

lar remark applies to different ages, places, subjects and 
authors. 

Usage is learned from passages or expressions where 
circumstances render the exact meaning obvious, as when 
we observe the occasions on which the expression " How 
do you do ?" is used. The meaning then becomes clear, 
whereas it is quite a mystery to a person who observes 
it for the first time in a book. In many cases, the sense 
is fixed by the immediate context, as if we notice the 
answer — " I am quite well," given to the preceding ques- 
tion : and when the usage is thus ascertained, it may be 
applied to remove the various difficulties which it occa- 
sions. 

The usages of a particular author are best ascertained 
from his own works, although they are frequently point- 
ed out in grammars and dictionaries : but much assist- 
ance may be derived from an acquaintance with his bi- 
ography, and the circumstances in which he was placed, 
as well as the history of his age and country. 

The peculiar usages of various countries and ages are 
best learned from their respective authors; and many 
of them are pointed out in grammatical and archaeolog- 
ical works. But many are best learned from a good 
knowledge of the nation's public and private life and man- 
ners. The corresponding terms for artificial objects dif- 
fer, of course, as much as the objects themselves. Thus, 
the words writing, auger, plough, coat, &c, have differ- 
ent shades of meaning, in different ages and countries. 
The corresponding words expressive of mental objects 
sometimes differ still more widely. Thus, among the an- 
cient Romans, pious meant dutiful or well-behaved, and 
religion denoted only the rites and ceremonies pertain- 
ing to the worship of the gods. 

Many words change their significations gradually, from 
age to age ; and, therefore, the age, as well as the coun- 
try, of the author must be noted, although the language 
may not have undergone any radical change. The sig- 
nifications of many words used by English authors of the 
fourteenth century, for example, differ widely from those 
which they bear al the present day. 

In some cases we must consider, not only the age and 
country, but also the dialect, or local usage : and here we 
must interpret the expressions according to the peculiar 
dialect of their author. 



Sec. 4.] Inteepeetation. 205 

The subject of discourse, also, requires attention : for 
many terms have, not only a general and a technical 
meaning, but several kinds of each ; and the subject is 
frequently an important guide in determining which of 
these ought to be adopted. We should generally attrib- 
ute to such words the peculiar sense which they usually 
bear, in the subject in which they occur, or among the 
class to which the author belongs. 

The character, circumstances, objects, and pursuits, of 
an author, are often of great importance in determining 
the sense of his expressions. It is also necessary to note 
his general style. Some follow common usage so closely 
that their compositions present no peculiarities which 
can cause any difficulties of interpretation, while others 
follow an opposite course. The former are generally su- 
perior, in every important respect. Men of an oi-iginal 
cast of mind frequently exhibit marked peculiarities of 
style : but the highest order of minds is charactei'ized by 
the clearness and precision, as well as the force of their 
style. 

A knowledge of individual peculiarities is occasionally 
of more consequence than that of an author's age, since 
some affect the style of former generations, while others 
study novelty of expression. But this has generally 
been done by inferior authors, who attempted to excite 
by their manner a degree of attention which could not 
be secured by their matter. 

Individual peculiarities often affect language, by lead- 
ing to the employment of terms in a technical sense, 
when they should be used in their more general signifi- 
cation ; and persons often err in using the technical 
terms with which they are familiar, instead of the appro- 
priate expressions. An old seaman's dialect generally 
shows many instances of this kind. Here we should 
look to the usage of the class to which the individual 
belongs, for an explanation of his meaning. Thus, ambi- 
guities in contracts are often removed by referring to the 
usages of the trade or vocation to which they refer. Dif- 
ficulties of this kind are sometimes surmounted by ob- 
serving the conduct of the party, either when he em- 
ployed the expressions or at some other time, just as we 
learn the signification of terms wholly unknown, by ob- 
serving their applications. 

The character of an author's nation ought not gener- 



206 Language. [Chap. XI. 

ally to be overlooked, in interpreting his language, as it 
frequently, to a great extent, controls individual peculiar- 
ities. Nations of ardent dispositions and undisciplined 
intellects are apt to use language stronger than truth 
warrants, while that of men of cooler dispositions and 
more discriminating judgements are to be taken much 
more literally. The lofty terms of the former often mean 
much less than the more sober expressions of the latter. 

8. Where several meanings are admissible, roe should 
generally adopt that which best harmonizes with the con- 
text, the author's circumstances, views, and objects, and the 
character of those whom he addresses. This rule is based 
on the assumptions that one part of a composition gener- 
ally harmonizes with another, that an author will employ 
words in the sense best adapted to promote his objects, 
that his expressions have a meaning, and only one real 
meaning, and that he will endeavor to render himself in- 
telligible to those whom he addresses. These assump- 
tions generally hold true of the language of sensible men, 
who speak or write with proper objects in view, and on 
a subject which they understand. But when the author 
is a simpleton, or when he composes with other objects 
than to instruct, or deal fairly with those whom he ad- 
dresses, this rule does not apply. 

The proper application of this rule requires some 
knowledge of the general nature of the subject, the au- 
thor's particular character and objects, and also the char- 
acter of those whom he addresses. These may be learn- 
ed partly from the general tenor of the language, and 
partly from other sources, such as the testimonies of con- 
temporaries, acquaintances, or persons similarly circum- 
stanced. 

In the case of spoken discourse, the application of this 
rule is facilitated by observing the speaker's gestures, 
looks, and tones of voice. "We are thus enabled, in many 
cases, to distinguish irony and other figures from literal 
speech, and to ascertain the force and purport of the lan- 
guage, without any difficulty. In written discourse, no 
such aid is generally available : but we may often ascer- 
tain the true meaning by referring to analogous expres- 
sions, or to the author's direct explanation of the same 
subject or the passage in question. 

A frequent violation of this rule is, to interpret an ob- 
scure or ambiguous passage so as to make it clash with 



Sec. 4.] Interpretation. 207 

others which admit of only one interpretation, and then 
to force a meaning on the latter of which they do not ad- 
mit, in order to make them harmonize with the false sig- 
nification previously attached to the former passage. It 
is evidently absurd to force what is clear into conformi- 
ty with the supposed signification of what is dark. The 
proper course is, to attach to words no signification 
which they will not fairly bear, and to interpret what is 
obscure or ambiguous so as to make it tally with what 
is free from any such difficulty, and rightly admits of 
only one meaning. 

This rule is frequently inapplicable to the joint compo- 
sition of different persons, who entertained conflicting 
views of the subject, such as state papers, laws, treaties, 
and contracts. As these often speak the language and 
opinions of different authors, in their various parts, they 
may be quite inconsistent with each other, while we may 
have no means of knowing the author of any particular 
part. The same remarks apply to the different compo- 
sitions of a person who has changed his views in the in- 
terval, or who, at one time, expresses his own opinion, 
and at another time, those of other parties, whom he 
wishes to please. 

Sometimes the same part of a joint composition has 
different meanings, because its authors understood it dif- 
ferently, or pretend that they did so, as in many cases 
of contracts. 

With regard to all joint compositions, the safest course 
generally is, to adhere to the sense given by the other 
rules of interpretation, exclusive of the present, and, if 
these do not give a definite signification, to attach to the 
language no precise meaning whatever. 

Sometimes expressions apparently very precise, are, in 
reality, ambiguous, owing to extrinsic circumstances, as 
where a man wills his large English Bible to his son John, 
and it turns out that he left two such Bibles. Here we 
should first ascertain, from extrinsic evidence, the facts 
affecting the sense, and then apply the ordinary rules of 
interpretation. 

A frequent source of difficulty is, the uncertainty which 
exists as to what may be implied in the expressions : for 
we are left to infer the author's meaning from words 
which, of themselves, may convey no precise or unequiv- 
ocal signification. The authoi''s character, object, and 



208 Language. [Chap. XL 

circumstances, and the context of the discourse, are the 
principal guides for removing such difficulties ; and where 
these fail to do so, the only safe course generally is, to 
let the expressions go for nothing. 

Even where an inference may be necessarily deducible 
from a person's language, we are not always warranted 
in assuming that he intended to convey it : for he may 
either have overlooked it, or not discerned the necessary 
connection. We may generally infer that a person im- 
plies what one of his character and in his circumstances 
naturally would, but it is only where his character, or 
the immediate and palpable nature of the inferences ex- 
cludes other suppositions, that we can safely assume he 
meant to express the inferences, unless we have some 
extraneous proof that such is the case. 

Where we are obliged to rely on translations, we must 
look carefully to the context, and to similar or corre- 
sponding passages, either in the same or in other authors, 
wherever w T e encounter a serious difficulty; and much 
aid may be derived, in all such cases, from comparing in- 
dependent translations of the same passage. 

The proper application of the rules of interpretation 
require freedom from the influence of prejudice, and, in 
many instances, extensive and careful research and con- 
sideration. Hence misinterpretation has been a thing of 
very frequent occurrence, and a prolific source of perni- 
cious errors. The interpreter strongly wished that a 
certain interpretation should be true, and consequently 
he adopted it ; or he wished that the true meaning should 
be false ; and therefore he rejected it. 

There is a general prejudice in favor of interpreting 
the language of every one of whom we think favorably, 
so as to make it harmonize with our own views of what 
is true, right, or expedient. It is peculiarly apt to mis- 
lead us where we are not, in reality, well acquainted 
with the subject, and yet are not fully aware of the ex- 
tent of our ignorance. We should remember that what 
ice think or would have done, is no criterion of what 
others thought or did. 



Sec. 1.] Signs. 209 



CHAPTER XII. 

OF EVIDENCE. 

§ I. General Principles of Evidence. — Two kinds of Signs. — 
Conclusive Signs. — How ascertainable. — Three classes of Probable 
Signs. — Mode of determining the value of a Sign. — On what the 
general credibility of Testimony is based. — Influence of Witness's 
moral Character. — Means of determining the combined force of 
several independent Evidences. — Circumstantial Evidence. — When 
satisfactory, and when not. — Criterion. — Principles of its Applica- 
tion. — Defects of Circumstantial Evidence. — Means of determining 
the degree of Probability. — Caution. 

Signs are either conclusive, or only probable, evidence. 
They are conclusive when they are known, by induction 
or any other means, to be incompatible with the falsity 
of the proposition in question, or to be uniformly con- 
nected with it, and never to accompany any other state 
of things, except in some peculiar circumstances, which 
are absent in the case under consideration. Thus, the 
appearance of frost proves that the weather has been 
cold, and the mercury standing very high in the ther- 
mometer is a sure sign that it is warm. 

The usual modes in which a phenomenon is shown to 
be a conclusive sign of something, is, by proving that 
they are connected as cause and effect, or that they are 
both effects of a known cause, or that they are connected 
as premise and conclusion. 

Signs are only probable evidence in the three follow- 
ing cases. 

1. Where they are only generally, and not uniformly, 
connected with the thing in question. The appearance 
of swallows is only a probable sign that spring has come, 
since they sometimes appear before that season ; and the 
mercury standing very high in the barometer is only a 
probable indication of fair weather, since that phenome- 
non is sometimes speedily followed by a storm. 

2. Where they are sometimes connected with other 
things also. A person's ceasing to breathe is only a 
probable sign of death, since that sometimes happens to 
one who is still alive. 



210 Evidence. [Chap. XII. 

3. Where they are merely known to have accompanied 
it, in all the cases observed, but there is no proof that they 
will do so hereafter. The appearance of comets, in an- 
cient times, was followed by calamities; and hence it 
was inferred that they portended the latter, — whereas 
we now know that they have not the least connection 
with each other. 

In judging of the value of a particular sign, as an evi- 
dence of the proposition under consideration, we should 
first ascertain its real character, and then attach to it the 
precise degree of weight which that warrants : other- 
wise we are very liable to be misled by prejudices and 
preconceived opinions. 

The general credibility of testimony is based on the two 
following facts. 1. It requires an effort, for which some 
motive must exist, to invent a falsehood, or to conceive 
things differently from what actually occurred : for this 
is what naturally presents itself to our Memory or Ap- 
prehension. 2. The remembrance of a lie is always more 
or less painful, since we sympathize with the party- de- 
ceived, and disrelish the thought that the falsehood may 
be detected, and possibly punished, either directly, or by 
loss of character for veracity, and withdrawing future 
confidence. 

These principles operate even on the most immoral 
and unfeeling. Hence people will never lie, unless they 
have some object to effect by doing so ; and, when there 
can be no such object, they will testify truly. The ob- 
jects that will induce a person to lie, depend on his char- 
acter. Some lie habitually, for very trifling objects, 
while others adhere to truth amidst the strongest tempt- 
ations to the contrary. The latter are guided by cer- 
tain moral principles, or fixed rules of conduct, which 
render their testimony faithful, under circumstances 
which would lead the former to falsify egregiously. 

In many cases, there are various evidences, which all 
go to prove the same conclusion ; but every one of them, 
taken separately, affords only a probability of its truth. 
Here we should consider whether the falsity of the con- 
clusion is compatible with all the evidences, taken to- 
gether. If so, there is only a probability that the con- 
clusion is true. But if the reliable evidences are so nu- 
merous as to exclude the supposition of their being all 
fortuitous coincidences, the conclusion is established. 



Sec. 1.] Ciecumstantial Evidence. 211 

Circumstantial evidence consists of signs or testimo- 
nies from which the proposition in question may possi- 
bly be legitimately inferred, but Avhich do not directly 
prove it. It is sometimes more satisfactory than direct 
testimony, as being less liable to mislead us from the 
negligence or fraud of witnesses. It is frequently easy 
to state a simple direct falsehood which, if true, would 
decide the question, while it may be difficult to show the 
falsity of the statement, owing to its simplicity and con- 
ciseness ; but it is extremely difficult to invent a series 
of circumstantial proofs the character of which cannot 
be easily detected by a careful examination of them, and 
comparing them with known truths. 

This kind of evidence is always unsatisfactory where 
the circumstances are not so numerous and direct as to 
exclude the supposition of fortuitous connection, or 
where one circumstance disproves the conclusion drawn 
from another. The criterion of conclusiveness is, that 
when all the facts proved are certainly incompatible with 
any supposition but one, it is proved to be true. In all 
other cases, circumstantial evidence can prove nothing 
more than a probability. 

Whether the circumstances of a particular case con- 
form to the criterion or not, can be decided by no gen- 
eral rule, but only by testing them by the proper princi- 
ples, and then fairly weighing the whole. If it does not 
appear that the point in question is a necessary inference 
from the facts established, it is not proved, although it 
may have been rendered highly probable. 

It is further to be observed that we are liable to err 
in drawing the inferences from the circumstances proved, 
and that prejudices are apt to make the Imagination sup- 
ply the links that are wanting in order to make the chain 
of evidence complete, while the facts are often made 
known to us by testimony, which is liable to deceive us, 
as in other cases. Sometimes, also, the apparent signs 
may have sprung from causes quite different from those 
by which they are usually produced, as where a stranger 
may have been handling a thermometer, unknown to the 
investigator, or stolen goods are secretly conveyed into 
the house of an innocent man, in order to avert suspicion 
from the thief. Sometimes, on the other hand, the usual 
signs are removed or concealed either from design or ac- 
cident, as where a murderer hides the weapon of destruc- 



212 Evidence. [Cuap. XII. 

tion, or a servant takes water from a rain-gauge, without 
its being known. 

The degree of probability established by the circum- 
stances, depends on their force, independence, consisten- 
cy, and number. If several of them are dependent on 
one, or so connected with it that they must be true if it 
is true, all are tantamount to one only : and, in order to 
entitle the circumstances to any weight, they must not 
materially conflict with each other ; else the inconsistent 
class will destroy the force of the rest. 

This kind of evidence is susceptible of every degree 
of probability ; and, therefore, we should beware of either 
receiving or rejecting it indiscriminately. Every case 
should stand on its own merits. The probability is often 
so strong that we should unhesitatingly act upon it, as 
if it were a certainty, while it is often so much the re- 
verse that it is of no real value, except to suggest the 
course of further investigation. 

§ 2. Ckiterions of Testimony. — Importance of Testimony. — (1) 
Witness must have had means of knowing. — Usual Requisites. — 
General and Special Testimony. — Means of ascertaining witness's 
Credibility, on this head. — (2) He must have paid Attention. — 
Common sources of Inattention. — Partial Attention. — Where this 
point requires particular Consideration. — Means of determining the 
degree of attention given. — (3) Testimony must not be corrupted 
by Bias. — Kinds, influence, and sources of Bias. — How affected by 
individual Character. — Indications of its Absence. — Means of as- 
certaining its Existence, Character, and Influence. — (4) Testimony 
must not be a doubtful Inference. — Two classes of Inferences. — 
Various Sources of Error, and Means of avoiding them. — (5) Mem- 
ory must not be in fault. — Influence of Bias on Remembrance. — 
Means of obviating its Defects. — Frequent Difficulty, and means 
of surmounting it. — (G) Witness must possess a competent Under- 
standing. — Children's Testimony. — Indications of Defect. — (7) 
Testimony must be free. — Effects of Torture, Threats, Promises, 
and Suggestions. — Means of ascertaining whether they have op- 
erated. — (8) Testimony must be properly expressed, and faithfully 
transmitted. — How defects of this kind may be discovered. — Con- 
curring Testimonies. — Nature of the Statements. — Common proof 
of Invalidity. — Caution. — Discrepancies. — Important Distinctions. 
— Sources and Character of apparent Discrepancies and minor In- 
accuracies. — Real and material Discrepancies. — Means of sur- 
mounting Difficulties. — Particular use of Signs. — Probable Testi- 
mony. — Its Nature and Tests. — Caution. — Influence and Effects 
of Prejudices, in judging of Testimony. — Various kinds of Proba- 
bilities, and principles applicable to them. — Two futile Distinc- 
tions. 

The subject of testimony is of the utmost consequence, 



Sko. 2.] Ckiteeions of Testimony. 213 

as by far the greatest and most important parts of hu- 
man knowledge are based on it ; and it is also frequent- 
ly attended with difficulty. Hence its principles demand 
a diligent study and a careful application. 

To render the testimony of an ordinary witness con- 
clusive, as to the point which it professes to prove, it must 
generally possess the following characteristics. 

1. The witness must have possessed the means of know- 
ing what he testifies. The thing declared to have been 
comprehended must have been within the range of the 
proper faculties, in circumstances where they could act 
effectually ; and these must have been in a sound condi- 
tion, or at least not seriously deficient from disease or 
natural defect. The dim-sighted cannot see distinctly, 
nor can the deaf hear aright. In the case of sight, the 
object must not only be sufficiently near, but there must 
be enough of light, and not much more : men cannot see 
clearly in the dark ; and a dazzling glare of light is equal- 
ly unfavorable to proper vision. In the same way, sounds 
may be either too loud or too low for distinct hearing. 

If the requisite organs are sound, defects of others do 
not generally impair the testimony. It is no objection 
to a witness's statement regarding what he saw, that he 
is deaf. . Indeed a defect of one faculty frequently con- 
centrates the attention so closely on the objects of that 
which is sound, as to render the comprehension and re- 
membrance of them unusually distinct and vivid. It has 
often been observed that the blind mark and remember 
what they hear, and the deaf, what they see, better than 
those who labor under no such defect. 

Testimony is of two kinds, general and special. The 
former alleges, not the particular things actually witness- 
ed, but some generalization or inference from them : the 
latter states only what was directly comprehended. A 
person is incompetent to give a general testimony where 
he is not a judge of the subject : but such a restriction 
does not apply to special testimony. Thus, a man who 
is quite ignorant of seamanship, is incompetent to testify 
whether a ship of which he was aboard, was worked 
rightly at sea, during a tempest : but he may state the 
particular facts that he noticed, and aid mariners in form- 
ing a correct opinion. 

The credibility of a witness, on this head, can be gen- 
erally ascertained from a knowledge of his circumstances 
when he comprehended what he testifies. 



214 Evidence. [Chap. XII. 

2. The witness must have sufficiently attended to what 
he testifies. If his attention was absorbed by something 
else, or if he was indifferent, or so prejudiced that he did 
not fairly observe the object, his testimony is evidently 
unreliable. A partial degree of attention may enable a 
witness to testify correctly regarding the main facts : but 
in such cases little reliance can be placed on statements 
of details. In order to entitle these to credit, it must ap- 
pear that the witness paid particular attention to the 
subject, and that he does not mistake for an apprehen- 
sion what was only a conception, more especially if he 
belongs to that class of persons who are apt to be as 
much occupied with what they fancy as with what is 
present to their senses. 

The degree of attention given can be generally learn- 
ed, either from the witness's character and tastes, or 
from the nature of his statements. If these are full, and 
at the same time minute, attention may be inferred, 
Avhile vagueness and confusedness of statement indicate 
inattention, in the absence of any design to conceal or 
mislead. 

3. The testimony must not be wilfully corrupted from 
bias. In order to render a testimony quite reliable, the 
witness must be Avilling to relate the exact truth : other- 
wise it will be misrepresented by suppression, distortion 
or false additions. The bias may be either friendly or 
hostile. The former leads a witness to represent things 
more favorably for the party on whose behalf he testifies 
than truth warrants : the latter tends in the contrary di- 
rection. 

The sources of bias are as numerous as the desires of 
the human mind : bxit the most prevalent are, self-inter- 
est, ambition, the love of ease, the love of the marvelous, 
vanity, and malice. Strong party feelings seldom lead to 
actual lying, where they are unaccompanied by baser de- 
sires; but they frequently produce concealment, exag- 
geration or distortion ; and hence the testimony of par- 
tisans is justly liable to be suspected of such defects. 

Where we are ignorant of a witness's character, we 
should not admit his unsupported testimony as conclu- 
sive, if there is room for the influence of bias : but where 
we know him to be strictly veracious, we may receive 
his statements without suspicion, wherever he could err 
only from conscious 'falsehood. In many instances, his 



Sec. 2.] Ceiterions of Testimony. 215 

veracity appears from the accuracy of his statements, as 
we learn from other sources, while it is sometimes estab- 
lished by the evidence contradicting his bias. Where a 
witness testifies against the prejudices or cherished views 
of himself or his party, and, more especially, where he 
exposes himself to pecuniary loss, suffering or general 
odium, by his testimony, without reaping from it any ad- 
vantage that could lead him to falsify, we may consider 
his statements sufficiently free from the influence of bias. 
This conclusion is often corroborated by their exhibiting 
the ai'tlessness, straightforwardness, candor, precision 
and minuteness which characterize faithful testimony, 
just as we often detect bias and fraud by the contrary 
qualities. 

Where the testimony is otherwise unexceptionable, 
but it may possibly have been influenced by bias, we 
should receive it unhesitatingly only so far as it could 
not have been affected by the bias, and suspend any opin- 
ion as to the rest of it till we obtain further proof. Where 
the witness's character is known, we have only to determ- 
ine whether there is any bias strong enough to have 
materially affected his testimony. 

The existence and nature of the bias may be frequently 
learned from the witness's nation, profession, party, age, 
moral character, or peculiar relation to the testimony, as 
where he was himself concerned, and is anxious to show 
the best phase of his own conduct, or where some of his 
intimate friends or near relations are concerned. In oth- 
er cases, these are learned from the sweeping or unquali- 
fied nature of the statements, laudatory or contemptuous 
expressions, and the manifest exaggeration, extenuation 
or coloring of the testimony. Sometimes they are de- 
tected by comparing the statements with those of an im- 
partial person, or one of opposite bias, and by his evi- 
dent desire to have us believe a, particular thing. 

Bias is sometimes discovered from the witness's hesi- 
tating before making his statements, for the manifest 
purpose of avoiding self-contradictions, and rendering his 
falsehoods plausible. At other times, it appears from the 
statements being vague, studied, evasive, impertinent or 
flippant, by the witness's pretending to forget what he 
could not but remember, by his avoiding definite asser- 
tions where he can be contradicted by other testimony, 
while he speaks positively and precisely where he cannot, 



216 Evidence. [Chap. XII. 

or by his stating all that makes in favor of a certain con- 
clusion, while he suppresses things of a contrary tend- 
ency, which he must well know. We should, however, 
distinguish the hesitation of bashfulness from that of 
bias, which can generally be done from observing the 
witness's whole manner, or his relation to the matter in 
question. 

The extent to which bias has influenced the testimony, 
and the allowances to be made for it, may generally be 
learned from the circumstances of the case, or the testi- 
monies of other witnesses ; and, in many instances, it may 
be ascertained by compai-ing one part of the statements 
with another, or with what we previously knew of the 
subject. 

4. The tiling asserted must not he a doubtful inference 
from what teas actually witnessed. Inferences are fre- 
quently drawn with such rapidity that we mistake them 
for comprehensions, while they are sometimes erroneous. 
Hence witnesses have thus frequently testified untruths. 
The inferences are generally drawn correctly, and, as was 
formerly explained, we may admit them without hesi- 
tation. But some extend such inferences beyond due 
bounds. They will say, for instance, that they saw or 
felt such things when they only apprehended something 
which they believed to be tantamount, but which was, in 
reality, very different. Biased and careless witnesses are 
especially liable to fall into this error, but it often results 
from a general illusion. Instances occur in the general 
belief regarding our seeing the heavenly bodies moving, 
and the distances of objects. 

Sometimes a witness makes a statement as if upon his 
own personal observation, when, in fact, he derived his 
information wholly from others. Such testimony, at the 
best, directly proves only what the witness was told ; 
and the accuracy of the transmission must be tested by 
the circumstances attending it. The manifest relation 
of the witness to the thing testified, or the nature of his 
statements, often enables us to ascertain whether he 
speaks from personal observation ; and, in other cases, 
this can generally be learned either from the witness him- 
self or from other parties. 

5. It tnust appear that there is no ground to suspect a 
failure of Memory. When persons testify regarding 
things which they witnessed long ago, they are very apt 



Sec. 2.] Ckiteeions of Testimony. 217 

either to forget them altogether, and say they never com- 
prehended such a thing, or to confound them with what 
they apprehended or imagined on some other occasion ; 
and hence, where their testimony is unsupported by oth- 
er evidence, it is seldom conclusive, except as to matters 
which they could neither forget nor mistake. The Mem- 
ory of some, again, is so feeble, and their Imagination so 
active, that they can hardly distinguish what they re- 
member from what they only conceived, after the lapse 
of a few days ; and hence their uncorroborated testimony 
is of little value. Persons of this class are generally dis- 
covered by the palpable errors in their testimonies. 

The bias and general character of a witness affect his 
remembrance, as well as his apprehension, because we 
remember what strongly interests us much better than 
what we view with indifference. Hence a witness fre- 
quently remembers well one part of what he apprehend- 
ed, and wholly forgets the rest. Consequently, unless it 
appears that the witness felt equally interested in all that 
he may have apprehended, his having no recollection of 
one part affords no strong proof that it was not present. 

The immediate defects of a witness's Memory may 
have been obviated in several ways. He may have accu- 
rately written down what he observed at the time of its 
occurrence, or before his recollection of it failed, and he 
may have a distinct remembrance that the writing is full 
and correct throughout, while he can identify it ; or he 
may have perused a written statement made by another, 
while the occurrences or things witnessed were fresh in 
his Memory, and he can still testify to its accuracy from 
his recollection ; or he may have faithfully related to an- 
other person what he witnessed, before he forgot it, and 
the latter may still have a perfect recollection of what 
was thus communicated to him, or may have written it 
down accurately, when he first heard it. In all cases of 
this kind, however, the various parts of the chain of evi- 
dence must be examined with care, in order to avoid 
false inferences. 

6. The witness must not be deficient in understanding. 
The statements of an idiot, a maniac, or a young child, 
are generally as worthless as those of persons who labor 
under a defect of Memory or the organs of sense ; and 
the testimony of one who labors under some hallucina- 
tion or delusion relating to the matter in question, is 

K 



218 Evidence. [Chap. XII. 

equally unreliable, although his intellect may be other- 
wise quite sound. 

A child's testimony is sometimes satisfactory regard- 
ing simple and striking facts which fell under his observ- 
ation ; and it frequently possesses the advantage of be- 
ing more free from bias than that of older persons : but 
the inexperience and volatile disposition of childhood, its 
great liability to imposition, and its strong tendency to 
mistake one thing for another, and draw false inferences, 
generally render its testimony unsatisfactory, and of lit- 
tle value except to corroborate other evidence. 

Where we are not otherwise aware of the witness's 
character, testimonies of this kind are usually detected 
by their puerility, incoherence or absurdity. 

V. The testimony must he the free and spontaneous 
statement of the witness, unaffected by torture, force, 
threats, bribes, promises, or suggestions. All these oper- 
ate like natural bias, and, in many instances, still more 
strongly. It was formerly a common practice to torture 
witnesses who would not otherwise testify, in order to 
extort the truth : but experience showed, what might 
have been easily foreseen, that such applications rather 
led the witness to declare what he knew was required, 
in order to be released from the torture, even where his 
testimony subjected him to severe punishment. 

Although this may be considered the extreme case, yet 
all similar methods of eliciting evidence are alike in prin- 
ciple, since they interfere with the fair statement of what 
the witness knows or remembers, and must generally lead 
to misrepresentation, if not to positive misstatement. 
Suggestions from others are equally objectionable, since 
they tend to make a witness confound what he remem- 
bers with what he only conceives, even where there are 
no susjjicions of collusion, which suggestions of this kind 
naturally excite. 

The relations, circumstances and conduct of the par- 
ties concerned, the character of the testimony, or the sub- 
sequent free statements of the witnesses, generally ren- 
der it easy to ascertain whether motives of this kind have 
operated; and, in many cases, there is not even any 
ground to suspect them. 

8. The testimony must be properly expressed, and con- 
veyed to us either directly, or substantially as it was orig- 
inally delivered. It would evidently mislead, either by 



Sec. 2.] Critekions op Testimony. 219 

being stated in language which, when fairly interpreted, 
conveyed an erroneous signification, or by the original 
terms being essentially altered, through omissions, addi- 
tions or substitutions. Defects of this kind are to be dis- 
covered by observing the witness's character and cir- 
cumstances, and the mode in which the testimony is trans- 
mitted to us. 

Where a testimony is unexceptionable on all the pre- 
ceding heads, it is evidently conclusive. But, in many 
cases, we have not sufficient information on one or more 
of them ; and hence it is necessary to determine the force 
of the testimony on other grounds. 

The concurring testimony of several independent wit- 
nesses affords certainty, in many cases otherwise doubt- 
ful. "Where the statements of one, although very unsatis- 
factory when taken alone, are corroborated by many oth- 
ers, while there is no reason to suspect collusion or un- 
conscious error, we justly consider the evidence con- 
clusive. For it is incredible that various unconnected 
persons, differently situated, should all invent the very 
same fictitious tale, or commit the very same mistake, 
unless there is some ground of illusion common to them 
all ; and where this exists, it is generally obvious. 

The absence of collusion or forgery is frequently evinced 
by various coincidences in the different testimonies, which 
are so indirect and recondite as to satisfy us that they 
could not have resulted from any kind of fraud. These 
frequently consist of incidental remarks or allusions, 
which are found to tally with the other testimonies only 
by examining them closely, and drawing various infer- 
ences, so that it would evidently baffle human ingenuity 
to forge such narratives, and yet escape real discrepancies. 
This conclusion is sometimes corroborated by the testi- 
monies exhibiting several apparently glaring inconsisten- 
cies, which no one capable of forging such testimonies 
could have overlooked, but which can either be recon- 
ciled, or are of such a character as not to invalidate the 
substantial accuracy of the evidence. 

The nature of the statements often entitles them to be- 
lief, independently of the witness's character, as where he 
states the results of recondite scientific investigations, on 
a subject of which he is ignorant, or plans and sentiments 
which are above his power of conception, if not above 
his comprehension. In cases of this kind, the testimony 



220 Evidence. [Chap. XII. 

is credible, because the witness could not have forged it, 
while its consistency with what is known from other 
sources, may show that the facts are not materially mis- 
represented. 

On the other hand, one of the most common means of 
ascertaining the invalidity of a testimony, is, its being at 
variance with what we know from other sources : for 
truth cannot be inconsistent with itself. Some state- 
ments are incredible, because they assert self-evident im- 
possibilities ; and others are so, because they are incon- 
sistent with conclusive proof. But we must beware of 
hastily assuming that this is the case, esjDecially where 
the witness's character is otherwise good : for we are 
very apt to be satisfied with fallacious proof of what we 
wish to be true ; and cases are not rare in which conclu- 
sive testimony has been rejected, on the ground that it 
contradicted known truth, when, in fact, it contradicted 
only cherished errors. 

In some instances, the worthlessness of the testimony 
is apparent from the fact that one part of it directly con- 
tradicts another, on points of great importance. This 
contradiction may exist between the different parts of 
one statement, or a witness's present allegations and for- 
mer statements which he made on the same subject ; or 
it may lie in the conflicting statements of different wit- 
nesses. Here we must distinguish between material dis- 
crepancies, which proceed from gross carelessness, for- 
getfulness or unfaithfulness, and those minor variations 
which generally exist in the testimonies of independent 
witnesses, or even between the different statements of 
the same witness. The former invalidate a witness's 
credibility, while the latter do not, but frequently estab- 
lish it. 

Mendacity, collusion and forgery are frequently de- 
tected by the absence of any palpable inconsistency with 
the belief of the person addressed, while a careful and 
extensive scrutiny will discover, in the different state- 
ments, serious violations of truth. A faithful witness, 
on the other hand, often makes statements which do not 
precisely tally with the opinions of those whom he ad- 
dresses, or possibly even with all his own allegations. 
But their substantial accuracy is generally confirmed by 
subsequent investigations and discoveries. At the same 
time these detect a false testimony, since every error is 



Sec. 2.] Discrepancies. 221 

necessarily inconsistent with some truth, which future 
researches or accidental discoveries generally bring to 
light. So numerous are the sources which gradually re- 
veal error or falsehood, by unfolding some truth which 
is inconsistent with it, that it is very frequently exploded 
by the gradual disclosures of time. 

Many discrepancies are only apparent, and arise from 
our misunderstanding or misinterpreting part of the tes- 
timony ; some proceed from a witness's stating as a fact 
a false inference which he drew from what he compre- 
hended ; while others spring from one witness relating 
what another overlooked or forgot, every one generally 
remembering only what interested him, or attracted his 
attention. Some proceed from one wituess suppressing 
part of what he apprehended, for reasons which can gen- 
erally be discovered, without much difficulty, by consid- 
ering his circumstances and character. 

Many real discrepancies rather confirm than invalidate 
the testimony, because, while they are of very little con- 
sequence, they indicate the absence of studied and fraud- 
ulent harmony. So numerous are the sources of error, 
that the entire absence of any variations regarding such 
matters as dates, places and numbers, is not to be ex- 
pected, under ordinary circumstances ; and, therefore, 
such variations do not generally affect a witness's credi- 
bility regarding the main points of his testimony, espe- 
cially when they are elicited by brow-beating bashful or 
timid witnesses. Discrepancies between different state- 
ments of the same witness often arise from a mere slip 
of the tongue or pen, or some other slight degree of in- 
attention, or a failure of memory regarding points of no 
consequence, or misinformation derived from others, so 
that they do not in the least affect his veracity, and ought 
to have little influence on his credibility. 

Where testimony is really contradictory or discrepant, 
on material points, we may either look for further evi- 
dence, or closely scrutinize the statements and character 
of the witnesses. We shall thus generally find an ab- 
sence of the marks of conclusiveness on one side or the 
other. The defect is often so manifest as to render the 
testimony on that side worthy of no regard. The state- 
ments of a veracious and careful witness are not in the 
least invalidated by their being contradicted by those of 
a notorious liar or fabulist. So, when one witness of 



222 Evidence. [Chap. XII. 

doubtful veracity states something which is omitted by 
another, of known credibility, and which the latter could 
have neither overlooked nor forgotten, the former state- 
ment should be disregarded. 

If the difficulty cannot be removed by any of those 
means, we can obtain only a probability, and not knowl- 
edge, unless Ave have recourse to better evidence, which 
we should always do, if practicable, in every case of dif- 
ficulty. 

The credibility of a statement may often be ascertained 
from the witness's former conduct. The chai-acters of 
men are generally so uniform and consistent, that one 
who lied yesterday is seldom found to be veracious to- 
day, and one who has been strictly veracious hitherto, 
will generally be found so hereafter. If a man has been 
found to adhere to truth, amid the strongest temptations 
to the contrary, and to have been constantly guided by 
rigid principles of veracity, we may safely believe his 
statements, provided he has not been misled. But if he 
is found to have generally yielded to strong temptations, 
although he may be veracious in ordinary circumstances, 
we can trust his unsupported statements only when there 
is no strong motive to falsify. If he has habitually lied, 
no dependence can be placed on his testimony except 
where there is evidently no possible motive for falsehood, 
which can seldom be safely assumed of such characters. 

The credibility of a witness may sometimes be ascer- 
tained by observing how he states facts with which wo 
are acquainted from other sources, and which form tests 
of his veracity, such as accounts of things discreditable 
to himself or his party, or things which militate against 
some of his favorite opinions or desires. But we must 
beware of trusting to doubtful testimony regarding a 
witness's character : for we sometimes receive the most 
contradictory accounts of a person's veracity, and it is 
folly to believe one stranger regarding the character of 
another, where he may have some motive for misrepre- 
sentation. 

When a testimony amounts only to a probability, signs 
often supply the deficiency, and produce certainty. If a 
stranger asserts that there has been a severe earthquake, 
at a particular time and place, his testimony may be con- 
firmed by palpable marks of its effects, such as rents in 
the ground and fallen houses. In such cases si ens either 



Sec. 2.] Probabilities. 223 

corroborate or refute the testimony, precisely like the 
statements of additional witnesses. They may simply af- 
fect its degree of probability ; or they may render it con- 
clusive on the one hand, or entirely invalidate it on the 
other. 

The probability of a testimony of this kind depends on 
the witness's circumstances and character. If he had 
good means of knowing the truth, and bears a fair repu- 
tation, there is a great probability that his testimony is 
true. But if his situation was unfavorable, and his ve- 
racity is very doubtful, his statements cannot be safely 
adopted, without corroborative evidence. If his state- 
ments have received a coloring from his prejudices, we 
should endeavor to ascertain its extent, and make due 
allowances. 

If there are several independent witnesses, the proba- 
bility will vary according to their number, their several 
characters and opportunities, the degree of attention 
they bestowed on the matter, the time that elapsed, and 
so forth. The probability may be so strong that we are 
justified in acting as if it were a truth ; yet we should 
beware of ever assuming it to be such, and rejecting, 
without due examination, any alleged proof which seems 
to contradict or impugn it. Proof should never be re- 
jected wherever we do not already possess certain knowl- 
edge : for it frequently happens that the highest proba- 
bilities are refuted by irrefragable proof. 

Mankind are apt to be greatly influenced, in the re- 
ception of testimony, by their views regarding its extrin- 
sic probability, or that which is based on the nature of 
the statements : but this is generally the effect of preju- 
dice. The unlearned frequently measure everything by 
their personal experience; and the learned often view 
subjects in the light of their own theories. Hence con- 
clusive testimony has often been rejected, simply because 
it contradicted the erroneous belief or strong desires of 
the party to whom it was addressed, while, owing to the 
same causes, worthless testimony was received as con- 
clusive. Some travelers have been deemed liars, for 
faithfully recording what they saw, while others have re- 
lated fictions, which were believed without doubt or hes- 
itation. 

Unexceptionable testimony is never to be rejected on 
account of the apparent improbability of the statement : 



224 Evidence. [Cuap. XII. 

for testimony can prove anything comprehensible, which 
is not self-evidently impossible, or demonstrably incon- 
sistent with known facts ; and, for such propositions, no 
unexceptionable testimony ever can be given, for the sim- 
ple reason that incompatibilities cannot co-exist. But 
we must beware of heedlessly assuming that anything 
professedly proved by reliable testimony, belongs to this 
class : for prejudice is apt to make us infer that a propo- 
sition is absurd or untenable, when, in truth, it is only 
distasteful to our wishes, or incompatible with our erro- 
neous opinions. 

Men have often admitted errors on inadequate testi- 
mony, because they appeared to them highly probable, 
while they rejected important truths, proved by conclu- 
sive testimony, simply because they appeared highly im- 
probable, which was confounded with what is impossi- 
ble. The proper course is, never to admit anything as a 
certain fact, whether probable or not, when the evidence 
is unsatisfactory, and never to reject anything which is 
proved by unexceptionable evidence, however contrary 
to our preconceived opinions or our wishes. To act oth- 
erwise is, to believe without any good ground on the 
one hand, and to disbelieve against conclusive proof on 
the othei'. The very improbability of a statement is oft- 
en a strong indication of its truth, since a liar would in- 
vent something more likely to be believed by those whom 
he addressed, and an honest and careful witness is more 
apt to pay particular attention to an extraordinary phe- 
nomenon than to one of a different character. 

Where, however, the testimony is not conclusive, and 
it only establishes a probability, we may set up another 
probability in opposition to it, and thus possibly nullify 
its whole force. 

The intrinsic improbability of a testimony, or that 
which flows from the witness's circumstances and char- 
acter, must be carefully distinguished from its extrinsic 
improbability, or that which is based on the nature of 
the thing testified. Where the former does not exist, 
the latter is entitled to no weight: otherwise this 
strengthens the former, or impugns an intrinsic proba- 
bility, to a degree proportional to its force. Where the 
extrinsic improbability conflicts with the intrinsic prob- 
ability, the resultant probability is equal to the excess 
of the weaker of these two elements over the stronger. 



Sec. 2.] Futile Distinctions. 225 

A distinction has been drawn between such things 
as are " contrary" and those which are " not conforma- 
ble" to our experience ; and it has been maintained that 
evidence of the latter is admissible, but not of the former. 

To render this distinction valid, it is necessaiy to make 
the phrase " contrary to experience" mean that we were 
actually present, in the case alleged, and experienced no 
such thing as is affirmed, while we were so situated that 
we must have done so, if it actually occurred. But the 
distinction would now be irrelevant, since it amounted 
to saying that we should not receive another's testimony, 
to contradict what we ourselves properly witnessed, a 
doctrine which, though unquestionably sound, is evident- 
ly foreign to the point. 

Another meaning of the dogma is, that we experi- 
enced nothing like what is alleged, while we were placed 
in circumstances where that might be reasonably ex- 
pected. In this sense, it is evidently absurd. It would 
require a man, for instance, who had seen innumerable 
mountains, to reject all testimony as to the existence of 
volcanoes, because he had never seen a mountain pour- 
ing forth fire or smoke. So, it would require us to re- 
ject all testimony regarding the fall of showers of stones, 
because we have seen many showers fall, but never one 
of that kind. 

The only other admissible meaning is, that the thing 
alleged is contrary to the experience of ourselves and all 
our friends and neighbours. This modification is not 
sounder than the former, as these persons' circumstances 
are generally the same as our own, so far as regards the 
matter in question. The fact that all our neighbours have 
uniformly seen the Sun in the south at noon, by no means 
proves that others do not see it in the north, at that time 
of day. The absurdity of the distinction, taken in this 
sense, is well illustrated by the case of the culprit, who 
offered to bring thirty witnesses, every one of whom 
could truly swear that they had never seen him commit 
the crime for which he was on trial, after three unexcep- 
tionable eye-witnesses had sworn to the contrary, the 
difference between the two classes being, that the latter 
were present, and the former absent. 

The sense which would include, under the expression 
" our experience," that of every individual of mankind, 
is evidently inadmissible, as in that case the dogma 
K2 



226 Evidence. [Chap. XII. 

would assume that the testimony is false, which was the 
very thing in question. 

A similar distinction has been drawn between improb- 
abilities based on previous experience, and those founded 
on the various ways in which a thing may happen. The 
former class, it has been said, are not legitimate subjects 
of testimony, but the latter are. It is sufficient to ob- 
serve that History abounds with instances of things ex- 
tremely different from what previous experience would 
have led us to expect ; and, therefore, this distinction is 
as futile as the former. 

§ 3. Various Kinds of Testimony, and Peculiarities of each. — 
(1) Explicit and Implicit Testimony. — Advantages of each. — (2) 
Immediate and Mediate Testimony. — Characteristics of the latter. 
— Why common Eumor is generally worthless. — When important. 
— Mode of testing the value of Mediate Testimony. — (3) Oral and 
Written Testimony. — Advantages and Disadvantages of the former. 
— Importance and Advantages of Written Testimony. — Effects of 
Lapse of Time. 

1. Testimony is explicit when it expressly declares the 
very thing in question : it is implicit when it only states 
something which directly inches it, or is a sign of it. 
In the latter case, the witness is sometimes unaware of 
the implication : and hence it often elicits truths which 
could be discovered in no other way, owing to the wit- 
ness's strong desire, or fixed determination, to conceal 
them: and such evidence here possesses the further ad- 
vantage of excluding the influence of bias, in coloring 
the statements, even where there is no attempt at con- 
cealment. Yet, where there is no difficulty of this kind, 
explicit testimony possesses the great advantage of being 
free from the risk of false inferences, to which we are al- 
ways more or less liable in the other case. 

2. Immediate testimony is, where the party who ad- 
dresses us personally comprehended what he relates : 
•mediate is that given by one who only heard or read 
what he relates ; and many parties may have intervened 
between the original witness and the last relater. 

As men are generally liable to forget or misunder- 
stand what they have read or heard, mediate testimony 
is seldom entitled to credit, especially where it has passed 
through many hands. It often contains a large admix- 
ture of truth : but it is frequently difficult to determine, 
with any great degree of certainty, which part is true 



Sec. 3.] Diffekent Kinds. 227 

and which is false. Even the most important part is 
sometimes entirely lost, or totally misrepresented. Hence 
the proverbial uncertainty of common rumor. 

Mediate testimony is particularly worthless where, as 
frequently happens, some of the relaters labor under any 
of the difficulties which invalidate immediate testimony, 
as where an unprincipled man hears something disrep- 
utable about one whom he strongly dislikes. But the 
immediate relater is sometimes a person of a different 
character ; and hence the muddy channel through which 
the statements have flowed is apt to be hidden from 
view. 

Where the object is, merely to ascertain what com- 
mon report says, such testimony is sometimes quite im- 
portant, as where a man prosecuted for slandering an- 
other, shows that the latter's reputation, as to the mat- 
ter in question, was previously very bad. 

In estimating the value of mediate testimony, we must 
first determine the degree of credit due to the immediate 
relater, and afterwards examine every part of the chain 
of evidence. If we find a material defect in any link, it 
establishes, at the best, no more than a probability, which 
must be sufficiently corroborated by some other evidence, 
before it is entitled to be received as satisfactory. 

Where a narrative includes both kinds of testimony, 
every part is to be tested by the proper criterion ; and 
it may thus be found that some parts are quite credible, 
and others as much the reverse. Herodotus' account of 
the Persian wars is mostly credible, because he obtained 
his information from eye-witnesses : but this cannot be 
said of his history of earlier transactions, which is much 
less reliable. 

3. Oral testimony is given by word of mouth : written, 
is that of a person who is not present, and whose written 
statements are read. The former possesses the advantage 
of allowing us to observe the witness's demeanor, and to 
obtain further information, or an explanation of difficult- 
ies, by means of questions. Suitable interrogations also 
enable us, in many instances, to test the witness's com- 
petency, and the character of his previous statements. 

On the other hand, the presence and appearance of a 
witness not unfrequently excites prejudices which lead 
to his statements being estimated either above or below 
their real value, whereas a careful consideration of his 



228 Evidence. [Chap. XII. 

testimony, by the light of other reliable evidence, and a 
knowledge of his character and peculiar circumstances, 
would obviate any such result. Immediate oral testi- 
mony, also, can be procured only during the original -wit- 
ness's lifetime, after which the advantages of this kind 
of testimony are lost. 

Written or printed testimony can be accurately com- 
municated to distant times and places, while it obviates 
the numerous errors arising from failures of memory, and 
enables us to contemplate the statements as often and as 
deliberately as we please. It also enables us to have re- 
course to the original evidence, instead of relying on hear- 
say, compilations or abridgements, all of which are liable 
to produce numerous errors, and which frequently mis- 
represent or suppress something of importance. 

There is generally less room for bias in written testi- 
mony, because the witness's prejudices are not so exten- 
sively concerned. An author frequently writes for dis- 
tant times and places, or at least for unknown readers ; 
and, therefore, he is less tempted to misrepresent than 
where his testimony has an evident bearing on immediate 
objects of desire, which may be secured by it. 

Another advantage of written narratives is, that other 
evidences by which they may be tested, are more inde- 
pendent, and consequently more free from bias. The 
people of a neighbourhood are all frequently influenced 
by the same prejudices, which is rarely the case with wit- 
nesses who live in distant ages and countries. The lapse 
of time tends to confirm true statements and disprove 
others, by revealing things which confirm the former and 
disprove the latter, while these are so unconnected and 
varied, that collusion, or accidental errors of any great 
consequence, are inevitably detected. Thus, ancient tes- 
timonies, which are corroborated by the successive dis- 
coveries of distant ages and countries, become more and 
more irrefragable as they become older, while false state- 
ments are gradually seen in their true light. 

While written testimony is of such great importance, 
it is sometimes attended with difficulties from which oral 
evidence is generally free. These we shall briefly dis- 
cuss in the following section. 

§ 4. Means of ascertaining the Origin asd Character of 
Wkitteh Testlmont. — (1) External and Internal evidences of 
Authorship. — In what cases the former are reliable, and in what, 



Sec. 4.] Evidence op Authorship. 229 

not. — Principles of decision regarding the latter. — Means of ascer- 
taining the Witness's Age and Country. — Important Eequisite. — 
Means of distinguishing spurious from genuine Compositions. — 
When it is, and when it is not, of consequence who wrote a Com- 
position. — Rules for ascertaining the Writer, in the former case. — 
(2) Sources of material Corruptions. — Eules for determining what 
parts are corrupted or spurious, and what, genuine. — Different Edi- 
tions. — How Abridgements may he distinguished from Originals. — 
Means of ascertaining the Age and Country in which a Manuscript 
was written, or a Book printed. — (3) Origin of Various Readings. 
— Where one only, and where several, are genuine. — Comparative 
purity of Manuscript and Printed Copies. — Effects of Time, in re- 
moving Errors. — Influence of Printing. — Rules regarding Various 
Readings. — General Character of these Readings. — (4) Means of 
distinguishing authentic from fictitious narratives. — Applications of 
this section. 

I. The evidences of the authorship of a composition 
are either external or internal. The former consists of 
the testimony of contemporaries or persons who lived 
near the period : the latter is, that which is afforded by 
the matter and style of the production. 

External evidence is to be examined like any other 
testimony. In the case of contemporary or very recent 
writings, it is generally conclusive, and free from any se- 
rious difficulty, as there is direct credible testimony : but, 
in regard to ancient compositions, it is often worthless, 
owing either to the witness not living sufficiently near 
the time when the work was composed, or to the testi- 
mony being spurious, or to the known mendacity or in- 
accuracy of its author. 

This testimony may consist either of direct statements, 
or of allusions, quotations or translations. As a book 
cannot be quoted or translated till it exists, the fact of 
such references being found proves that the composition 
is older than the one which contains the references. But 
these should be unequivocal ; and the age and origin of 
the work which contains them should be well known : 
otherwise they will rather mislead than enlighten. 

The supposed author himself sometimes testifies re- 
garding a composition attributed to him: but his evi- 
dence should be received with caution : for some dishon- 
est men have claimed the works of others as their own, 
while some have denied their real compositions. If the 
author's veracity is unimpeachable, however, such testi- 
mony is conclusive. 

The internal evidence is based on the various peculiar- 



230 Evidence. [Chap. XII. 

ities of thought and expression which distinguish differ- 
ent ages, countries, and individuals. A work which bears 
the characteristic and peculiar indications of a certain 
age and country, may fairly be inferred to belong to 
them, while one which lacks these, may be safely taken 
to belong to some other time and place. 

The evidence afforded by particular allusions is often 
conclusive, as to the time after which a work must have 
been written. A treatise on the Trojan War, that al- 
luded to the Crusades, must have been written after the 
tenth century ; and one which mentions the presidents of 
the United States of North America, cannot be older 
than the end of the eighteenth. It is possible, however, 
that a work may have been altered, so as to contain al- 
lusions to things much more recent than the original 
treatise. If the part containing the allusion is genuine, 
its evidence is conclusive : if not, the age of the compo- 
sition must be ascertained by other means. 

The authoi''s country may often be determined in a 
similar manner, because some nations were ignorant of 
things well known to others. A history of the Crusades 
could not have been written by a Japanese contempora- 
ry ; nor could a Roman history have proceeded from an 
ancient Hindoo. 

The application of the preceding principles requires an 
accurate knowledge of the real peculiarities of the differ- 
ent ages and countries, which were not always such as 
they have been represented. 

Compositions of which the authors are doubtful or 
unknown, have been mostly assigned to persons of whom 
we possess some genuine works : and, therefore, we can 
compare the composition in question with the latter. 
But, in so doing, we should beware of assuming that all 
the works of an author must be precisely alike, in every 
respect. His subject, time of life, and varying circum- 
stances and opinions, often produce marked diversities 
in an author's different works, although certain peculiar- 
ities are generally common to them all. We should, 
therefore, observe whether the differences in question 
are greater than may reasonably be attributed to those 
sources. 

The difficulty of detecting some spurious productions 
is increased by their having been designedly composed 
in imitation of the alleged author's real works, and their 



Sec. 4.] Evidence op Authorship. 231 

consequently adhering closely to his style and sentiments. 
But a close inspection will generally show their different 
origin. It is more difficult to imitate a person's style 
exactly, throughout a composition of any length, than to 
mimic his voice. The imitation will be either a spiritless 
copy of the original, as unlike as a corpse is to the living- 
person ; or it will exaggerate his peculiarities, so as to 
resemble a caricature. 

If the imitator is incessantly on his guard against any 
expression which would betray him, his composition will 
necessarily exhibit a constrained and affected mode of 
speaking, reminding us of a person walking on stilts, 
with an absence of originality and the ease which distin- 
guishes one who uses his own natural style. If, on the 
other hand, he should venture on new ground, and adopt 
some freedom of expression, his own peculiarities will 
appear, and some words will escape him which will at 
once betray the origin of the composition. 

The question who actually wrote a composition is fre- 
quently of no consequence. For, even where the author 
employed an amanuensis or one who wrote from his dic- 
tation, we may fairly presume that he either perused it 
himself or that it was read over to him, and all serious 
errors corrected, before it passed out of his hands. But 
this question becomes very important wherever the writer 
must have been the author, as it then becomes identical 
with that of authorship, which it may be the principal 
means of ascertaining. In such cases, there are the four 
following ways of ascertaining the writer. 

1. His own acknowledgement, which is quite satisfac- 
tory wherever his character and motives are above sus- 
picion, and he gives his evidence unambiguously ; but, 
in other cases, it may be entitled to very little weight. 

2. The evidence of a person who saw him write it, 
which is to be examined like other cases of testimony. 

3. The opinion of one who is familiar with the hand- 
writing. As various persons often write like each other, 
and the same person often writes in different hands, either 
from hurry, design, or gradual change, this evidence is 
seldom quite satisfactory ; and it generally furnishes only 
a probability. 

4. The opinion of one who is a judge of handwritings, 
and who compares the writing in question with others, 
the writers of which are supposed to be known. This 



232 Evidence. Chap. XII. 

method is still less reliable than the last, since we are 
apt to err regarding the origin of the writings used for 
comparison ; and the opinion of one who is not familiar 
with the party's handwriting is less reliable than that of 
a person who knows it well. 

II. Written testimony has sometimes been materially 
corrupted from design. In some instances, the corrupter 
believed that he was correcting the testimony, and re- 
moving errors, while he was only falsifying it : in other 
cases, he acted wilfully, from a desire to make it con- 
formable to his wishes. Here parts which exhibit any 
of the three following characteristics are to be rejected 
as interpolations. 

1. Where they do not exist in any good manuscript, 
or in any printed edition superintended by the author. 

2. Where the statements could not possibly have been 
made by the author of the work, on account either of 
his circumstances or his character. 

3. Where we have conclusive external evidence that 
the parts are either wholly spurious or materially altered. 
Such evidence may be found in the testimony either of 
the author himself or of persons who derived their in- 
formation directly from him, or examined a copy of the 
work known to be correct. 

A part is to be deemed genuine in the following cases, 
provided there is no conclusive proof to the contrary. 

1. Where it is found in all good manuscripts, or in a 
manuscript or printed copy examined by the author. 

2. Where there is conclusive external evidence of its 
genuineness. This may be found in the author's ac- 
knowledgement, either direct or indirect, (as by quoting 
it or alluding to it) or in the statements of parties who 
read or heard the original or obtained reliable informa- 
tion from those who knew. 

3. Where it forms an essential part of the composi- 
tion, which would be rendered unmeaning or absurd by 
its removal. 

Some variations are possibly alterations made by the 
author, in successive issues, in which case widely differ- 
ent copies may all be equally genuine, although the latest 
may be fairly presumed to be the best. In printed 
books, the date, place, printer, and preface, often enable 
us easily to distinguish the successive variations, which 
are occasionally so great as to render the various edi- 



Sec. 4.] Material Corruptions. 233 

tions, in reality, different works. But we seldom have 
such aids in the case of manuscripts. Yet the circum- 
stances and habits of ancient writers were such, that dif- 
ferent editions of a work can rarely be presumed to have 
emanated from the author, while unequivocal proof of 
such a thing can hardly be found ; and consequently we 
may presume that there is only one genuine version. 

It is sometimes doubtful whether a work is an origin- 
al composition, or only an abridgement, executed prob- 
ably by some other person than the author. Here we 
must generally rely on external evidence, as the question 
usually arises only where the original has perished. In 
other cases, differences of style and expression may clear- 
ly indicate that the abridgement was not made by the 
original author. 

In investigating the character of a particular copy, it 
is frequently important to know the age or country in 
which it was written or printed. The former can gener- 
ally be determined, to a great degree of accuracy, by ob- 
serving the language, orthography, divisions of lines and 
words, punctuation, contractions, abbreviations and dia- 
critical marks, embellishments and nourishes, material, 
and ink. These all varied so much, from age to age, 
that a careful examination of them will generally enable 
a person who has studied the subject, to determine the 
age of a manuscript within half a century. The country 
in which a manuscript was written, can frequently be as- 
certained by the same means, since it is found that dif- 
ferent countries adopted different forms and methods. 

The characteristics of the several ages and countries 
are ascertained from writings of which the origin is 
known, either from their nature or from immediate testi- 
mony. To the former class belong original deeds, char- 
ters, letters, proclamations and public records. Some of 
these, however, are counterfeit ; and, therefore, care is 
required to distinguish them from the genuine. 

Printed works generally indicate the place, printer, and 
year, on the title-page and its reverse, or at the end. But 
some books lack these, or give fictitious ones, in which 
case recourse must be had to the preceding methods. 
The character of the materials, and the appearance of 
the type, ink, and binding, often indicate their age and 
origin, while the printer is frequently known from his col- 
ophon, or peculiar device, at the end of the volume, or 
in the title-page. 



234 Evidence. [Chap. XII. 

III. A third difficulty, which frequently attends writ- 
ten testimony is, that there are various readings, or slight- 
ly different versions of it. These arose from various 
causes. The old copyists, who supplied the place of 
printing, before the use of that art became general, did 
not always detect or correct the accidental mistakes 
which occurred in their manuscripts, since this both im- 
posed labor and disfigured their appearance. Other er- 
rors arose from the same sources as spurious passages, 
and some proceeded from the marginal glosses of preced- 
ing copyists or readers being mistaken for omissions, and 
consequently inserted in the text. Others were caused 
by substituting a phrase which was better known for one 
which was becoming obsolete or belonged to another di- 
alect. Many arose from misreading or forgetting the 
original, and then substituting a similar but different ex- 
pression. 

It is also very possible that there may be several gen- 
uine readings of a passage, just as there may different 
genuine editions ; and the remarks already made regard- 
ing the latter, apply equally to the former. In modern 
authors, they are of common occurrence, and easily as- 
certained : but the case is frequently otherwise with old- 
er compositions, in which we have rarely any proof that 
more than one reading ever proceeded from the author. 

Printed copies are generally more accurate than an- 
cient manuscripts, because various errors are corrected, 
by means of proof sheets, before the impression is struck 
off; and they are also less subject to omissions or addi- 
tions, either accidental or designed, while they render im- 
practicable any subsequent alterations of all the copies 
of an edition ; and although printed copies are by no 
means exempt from errors, yet the critical comparison 
of good manuscripts or copies, and more care in printing, 
tend to produce more and more accurate versions, till a 
text is formed free from any serious error. 

Although a single copy or impression lasts only for a 
definite period, yet the arts of printing, photography, en- 
graving and stereotyping enable us to multiply accurate 
copies, or facsimiles of manuscripts indefinitely, so that 
the testimony can be preserved unchanged, to the remot- 
est times. 

The rules already given, regarding the genuineness of 
a composition, are equally applicable to this subject ; and 



Sec. 4.] Various Readings. 235 

the following are the principal additional rules, for ascer- 
taining the true reading : 

1. The oldest manuscript of an ancient author is to he 
preferred when other things are the same. But the rule 
does not apply where a later manuscript has been more 
directly derived from the original, or where a manuscript 
is found to have been either carelessly written at first, or 
afterwards corrupted. 

2. Where several genuine readings exist, the most re- 
cent is to be deemed the best. This rule assumes that 
the last reading expresses the author's most mature 
thoughts ; and, therefore, where the case is otherwise, it 
does not apply, as if a man in his dotage or in a fit of in- 
sanity should undertake to alter the productions of his 
better days, or should wilfully corrupt them, from some 
bad motive. 

3. The reading of the great majority of copies is to be 
preferred, unless there is conclusive proof that it is erro- 
neous. 

4. A reading which is conformable to the known views, 
sentiments or style of the author, is preferable to one 
which is not, unless the former is demonstrably erro- 
neous. 

5. A reading which gives a good or correct sense, is 
better than one which gives either nonsense or an erro- 
neous statement. This rule applies only to the testimo- 
nies of persons who are not destitute of sense or honesty. 

6. A reading which violates the idiom or grammar of 
the language, is to be rejected for one which does not. 
It is assumed that the author wrote with care, and knew 
the language : else this rule does not apply. 

7. Of two admissible readings, that which was most 
liable to be changed, is to be preferred. Thus, a reading 
at variance with the opinion of the copyists, or conflict- 
ing with some strong prejudice of the party addressed, is 
preferable to one which conforms to it. 

8. Of several readings otherwise equally probable, that 
which best agrees with the context, is to be preferred. 

9. A reading which is a manifest blunder or corrup- 
tion, is to be disregarded. 

10. The reading of a good is preferable to that of a 
bad copy, where there is no proof to the contrary. 

11. A good copy is known by its general accuracy, 
and its containing few manifest errors, or by the testi- 



236 Evidence. [Chap. XII. 

mony of persons who knew the original, or copies direct- 
ly and carefully made from it. 

12. An inaccurate copy is known by its abounding 
with unquestionable errors, its being evidently made 
without care, or by the testimony of those who know 
its real character. 

13. A printed copy of which the author corrected the 
proof sheets, is good : but if he did so carelessly, a copy 
diligently corrected from his original manuscript, may 
be better. 

14. Where all the copies of an early translation show 
no variations of a passage, its reading is equivalent to a 
copy of the age in which it was made. The rule assumes 
that there is no room to doubt the genuineness of the 
passage, or the mode in which the translator read his 
original : otherwise it is inapplicable. 

15. The preceding rule is applicable to quotations, if 
not made from memory. It is observable, however, that 
quotations are often made from memory ; and, in such 
cases, they are of little use in ascertaining the true read- 
ing. 

16. In modern compositions, the true reading may fre- 
quently be ascertained by referring to the original man- 
uscript, or to some person who directly knows that read- 
ing. But we must beware of mistaking an inaccurate 
copy, or the rough draught, for the original manuscript. 
The true original is the finished composition, and not 
the first copy. 

17. Conjectural emendations are allowable only where 
the text is certainly corrupt, while the proposed emen- 
dation harmonizes with the context, and has every appear- 
ance of having been the original reading. The obscurity 
of a passage does not justify the admission of such emen- 
dations, since it may ai-ise from our ignorance, and disap- 
pear after we have become better acquainted with the 
language and the subject of discourse. Hence the text 
might be corrupted, instead of being improved, by a too 
ready admission of emendations of this kind. 

Most various readings are of little importance, because 
they do not materially affect the sense. But some of 
them are serious ; and these abound in Avorks which have 
been copied very carelessly. 

IV. The fourth difficulty which sometimes attends 
written testimony, is, that we are left to doubt whether 



Sec. 4.] Fiction. 237 

the narrative is authentic or fictitious. Here we must 
examine the external and internal evidences, as when we 
are investigating the authorship, the determination of 
which will generally remove this difficulty also. 

The character of the composition may possibly be 
learned readily from testimony. Thus we learn that 
" The Life and Surprising Adventures of Robinson Cru- 
soe" is a fictitious autobiography, written by Daniel De- 
foe, though partly based on the real adventures of Alex- 
ander Selkirk. So we learn that Julius Csesar's " Com- 
mentaries on the Gallic War" is an authentic narrative, 
regarding real personages and events. 

Fiction generally betrays its character, either by its 
absurdity or its inconsistency with what we know from 
other reliable sources. If the writer gives dates, and 
the names of persons and places, we may compare his 
statements with what is otherwise known regarding 
them, when we shall generally ascertain the character of 
the narrative, with little difficulty. If he gives only fic- 
titious names, his testimony is not entitled to belief, un- 
less we possess other conclusive evidence of its authen- 
ticity. 

The character of a narrative is generally unfolded by 
subsequent researches or discoveries, regarding the sub- 
jects of which it treats, as in other cases of testimony. ' 
Thus, we learn that the accounts which several ancient 
authors give of the Pygmies, though long believed, are 
quite fabulous, while, on the other hand, numerous state- 
ments of ancient historians, which were long regarded 
as fictitious, have been confirmed by recent discoveries. 

This section is mostly applicable to all kinds of written 
composition, as well as to testimony in its narrower sig- 
nification, or that which regards only the witness's im- 
mediate comprehension, since the general modes of ascer- 
taining the origin and character of writings are the same, 
to whatever class they belong : and, so far as concerns 
our present purpose, everything which a person asserts, 
may be termed his testimony. 



238 Classification. [Chap. XIII. 



CHAPTER XIII. 

OF CLASSIFICATION. 

§ 1. Nature and Uses of Classification. — Definition of Classifi- 
cation. — Two kinds of it. — Naming essential. — How distinguished 
from Generalization. — Objects susceptible of Physical Classifica- 
tion. — Why this is preceded by the Mental Process. — Five main 
Objects of the latter, with Observations. — Division. — Important 
Distinction. 

Classification is, arranging together such things as 
resemble each other, and separating them from such as 
are unlike : and it is either mental or physical. The for- 
mer consists in determining what things are alike in some 
respects, and unlike others in the same respects, and dis- 
tinguishing them by a suitable name. The latter con- 
sists in actually arranging or assorting together physical 
objects, which have been formed into classes by the men- 
tal process. If a man has a lot of shells, he may first 
determine how many kinds there are, with the peculiar- 
ities of each, and give every class a name. This is the 
mental classification. When he places together all the 
shells that belong to the same class, and removes those 
which do not, this is physical classification. 

Naming the various classes is an essential part of clas- 
sification : for it is requisite to a proper remembrance or 
description of their several peculiarities. Hence a good 
system of nomenclature greatly facilitates induction ; 
and it is also requisite in order to secure the chief ob- 
jects of classification. 

Classification differs from generalization in comparing 
like with unlike, separating the two, and distinguishing 
every class by a suitable name. We might generalize 
if we had only one species before us : but classification 
requires us to compare individuals of several species. 
Generalization necessarily precedes classification, because 
we cannot classify objects till we have first ascertained 
their common resemblances, as well as their common 
differences. 

Physical or material objects alone are susceptible of a 
physical classification : for, although we may classify men- 



Sec. l.] Its Uses. 239 

tal phenomena, or the peculiarities of individual charac- 
ter, it is impracticable to arrange such things together. 

As physical classification is only an actual assorting 
of things, according to the dictates of the mental process, 
the latter must always precede it. 

The main objects of mental classification are the five 
following. 

1. To aid the Memory. The simple objects in nature 
are so numerous, and frequently so unlike each other, 
that we cannot remember the properties of any great 
portion of them, without arranging them in such a way 
that we can consider those which are alike consecutively, 
and thus obviate the necessity of running continually 
from one object to another extremely unlike it. This 
can evidently be effected only by means of classification. 

2. To facilitate induction. It is only after those things 
which are obviously alike have been arranged together, 
and separated from those which are unlike, that we can 
advantageously proceed to investigate their general prop- 
erties. We first ascertain individual facts, and then ex- 
tend our observations, till we establish some kind of gen- 
eralization. This is followed by a corresponding classi- 
fication, which is usually succeeded by an induction : and 
the latter often leads to an improved classification, which 
may prepare the way for a more extensive induction. 

3. To assist us in determining the character of an in- 
dividual. By simply ascertaining that it exhibits some 
characteristic mark of a class, we know at once that it 
belongs to that class, and possesses all its peculiarities, 
a thing which might otherwise be very difficult, or even 
impracticable. Thus, a zoologist can ascertain the gen- 
eral structure and habits of a quadruped from simply 
inspecting the bones of the foreleg. 

4. To prepare for physical arrangement. Where this 
preliminary process does not receive due attention, much 
confusion and loss of time are apt to result, because a 
thing cannot be found when it is wanted, or it cannot be 
ascertained what is wanted and what is superfluous. 
Proper physical arrangement of tools, apparatus and ma- 
terials is generally requisite to success in the arts, and 
also in many scientific investigations. 

5. To facilitate the communication of knowledge to oth- 
ers. This is sometimes termed division,' and it belongs 
to Rhetoric, rather than to Logic. Its leading principle 



2-iO Classification. [Chap. XIII. 

is, that things should be so arranged as to render an un- 
derstanding of the subject as easy, and the proofs as clear 
and conclusive, as possible. The principle that things 
the most like should be classed together, which is gener- 
ally supreme in Logic, should here be subordinated to 
the leading principle ; and many didactic treatises have 
been seriously injured by the author's confounding rhe- 
torical with logical classification, two things which often 
differ widely. 

§ 2. Peinceples and Methods op Classification. — General Prin- 
ciple of Classification. — Why there are many Special Principles. — 
Primary and Subordinate Principles. — What determines the form- 
er. — Seven Rules of Classification. — Essential and Non-essential 
Properties. — Classification of Organic Bodies. — Limits of Species. 
— Method of forming Genera, Families, Orders, and Classes. — Its 
Advantages. — Modes of naming Organic Divisions. — Application 
and Improvement of Principles. — Influence of Prejudices, and how 
avoidable. 

Similarity and diversity form the bases of all classifi- 
cation, the general principle being, that things which are 
similar are to be classed together, and separated from 
such as differ. But as things are like and unlike each 
other in various respects, there are many special princi- 
ples of classification. 

The primary principle of a classification is, that ac- 
cording to which things are grouped in the first instance, 
without allowing any other to interfere. A subordinate 
principle is, that according to which these groups are 
subdivided. 

The particular object of the arrangement determines 
which of several possible primary principles is to be 
adopted. The tax-gatherer classes men according to 
their residences and amount of property — the physiolo- 
gist, according to their corporal peculiarities — and the 
moralist, according to their ethical principles and con- 
duct. 

The following are the principal rules of classification : 

1. Every classification should be made according to a 
certain principle, with which no other should interfere. 
This rule is evidently requisite to prevent confusion. If 
a librarian, in first classifying his books, should at one 
time arrange them according to their subjects, and at an- 
other, according to the language in which they are writ- 
ten, volumes which treated of different subjects would 



Sec. 2.] Principal Rules. 241 

stand together in one place, and some which were com- 
posed in different languages would be found in juxtapo- 
sition elsewhere, so that both principles would be vio- 
lated. 

2. The principle should be definite, and not difficult of 
application. Otherwise it would be doubtful in which 
class a certain thing should be placed, and it might hap- 
pen to belong equally to two co-ordinate classes. The 
principle that all those plants are to be classed together 
which are essentially alike, although good as a general 
rule, is too indefinite as a general principle, because it 
leaves doubtful what essential likeness is. 

3. The principle should apply equally to all the things 
to be classified. Otherwise some part may be entirely 
omitted in the classification. The primary principle that 
all animals are to be classed according to the structure 
of the nervous system, is objectionable, because many 
animals have no such system. 

4. The principle should bring together those things 
which our object requires us to unite, and separate them 
from all others : else the classification would not answer 
the purpose. The principle that animals should be class- 
ed according to their apparent affinities, is bad, because 
these often differ widely from the real affinities. 

5. We should commence with the highest, and proceed 
gradually to the lowest divisions of our subject. As the 
former are separated by the greatest and most striking 
differences, they are generally the most easily made : and 
it is necessary to survey all that is to be classified, and 
form the higher divisions, before we can rightly fix the 
limits of the lower. Thus, in classifying all animals, we 
should begin with what are termed the sub-kingdoms, 
then proceed to the classes, thence to the orders, thence 
to the families and genera, and, lastly, to the species : 
otherwise it would be impossible to effect an harmonious 
and satisfactory classification. 

6. In all the sciences which treat of organic beings, as 
such, those things are generally to be classed together 
which are most like, or resemble each other in the great- 
est number of particulars. For the properties of such 
bodies are best understood and remembered, when ev- 
erything is arranged beside that which it most resembles, 
because this renders the points of similarity most appa- 
rent, and the mind naturally associates things according 

L 



242 Classification. [Chap. XIII. 

to their similarities. Hence plants should not be classed 
solely according to the structure of the organs of fructi- 
fication, because many plants have no such organs, and, 
in the case of others, the general structure is frequently 
unconformable to that of those organs. 

Essential and non-essential peculiarites should be dis- 
tinguished. The former are those which determine a 
thing to be what it is, and which cannot be altered with- 
out subjecting it to a complete structural change: the 
latter are such as may alter without producing any struc- 
tural change. In animals, the structure of the organs of 
nutrition and motion are essential properties, while the 
size, the color, and the appearance of the covering, are 
non-essential. Thus, a dog may be larger or smaller, 
black or white, straight-haired, curly-haired, or wholly 
hairless: but he could not have teeth and feet like a 
sheep's without ceasing to be a dog. This distinction 
leads to the following principle, which qualifies the sixth. 

V. Organic beings which resemble each other in essen- 
tial properties are to be classed together, although they 
may differ in others. Grayhounds must be classed with 
dogs, and not with hysenas, because they exhibit the es- 
sential peculiarities of dogs, although, in several respects, 
they resemble hyaenas more than they do poodles. 

In classifying organic beings, all those individuals are 
considered to be of the same species which differ only in 
such peculiarities as are found to vary in individuals 
known to have sprung from the same parentage; and 
where two individuals exhibit differences that are con- 
stant, and resist change, in those which have a common 
origin, under every vai-iety of external circumstances, 
they are considered of different species. 

In forming species into genera, a different course must 
be adopted : for the latter, unlike the former, are marked 
by no definite natural boundaries. The following method 
appears to be the best which has been hitherto proposed. 

A particular species which exhibits, in a marked de- 
gree, the chief peculiarities common to several very simi- 
lar species, is taken as the type, or best representative, 
of the whole group ; and all those species which resem- 
ble this type more than they do any kindred one, are 
classified with it, as being of the same genus. 

The number of types to be adopted, depends on the 
number of groups of species which exhibit such differ- 



Sec. 2.] Obganic Beings. 243 

ences that it would not comport with the object of the 
classification to arrange them in the same genus. 

The higher divisions of families, orders and classes 
may be formed in the same way, by adopting one of the 
subordinate divisions as a type. 

This method facilitates both classification and study. 
For we have only to compare a new or unclassed species 
with the types which it closely resembles, in order to de- 
termine its proper place, while the type gives the stu- 
dent a good view of the characteristics of the group, and 
the peculiarities of every species are easily acquired aft- 
erwards. So, the typical genus may represent its order, 
and the typical order, its class. 

A genus is distinguished by a generic name, and this 
is prefixed to a specific designation, to form that of the 
species, which thus indicates both the genus and the spe- 
cies. Thus, bos is the generic name of the ox tribe ; Bos 
taurus is the common ox, and J3os Americanus, the Amer- 
ican ox, frequently miscalled the buffalo. So, Quercics is 
the generic name of the oaks : Quercics pedunculata is 
the European white oak, and Quercics alba, the American 
white oak. 

The orders are named from some striking peculiarity 
or some well-known genus. Thus, Muminantia (cud- 
chewers) is the name of that large and important order 
of mammals which possesses four stomachs and rumi- 
nates ; and the rose gives name to the extensive vegeta- 
ble order of the Bosacem, including the rose, apple, pear, 
quince, plum, peach, cherry, currant, blackberry, goose- 
berry, raspberry, and strawberry, which are all charac- 
terized by alternate leaves, several sepals, regular petals, 
distinct stamens, and separate carpels. 

Families or sub-orders are generally named by modify- 
ing the name of some well-known genus. Thus, Canidce 
denotes the canine family, from canis, the term for the 
dog genus ; and Bovidce expresses the cattle family, from 
bos, the name of the ox genus. 

The classes, which are comparatively few in number, 
are designated either from one of their chief characteris- 
tics or from their common collective name. Thus, the 
class Mammalia is named from the. peculiarity of suck- 
ling their young, and the birds are termed Aves, which 
is only their ordinary Latin name. So, in Botany, one 
great class is termed Mitogens (out-growers), from their 



244 Classification. [Chap. XIII. 

growth being formed by new layers around that of the 
preceding season, such as the common forest trees of 
temperate regions ; and another is termed Indogens (in- 
growers), from the new growth being deposited among 
and within the old, such as the grasses, lilies, and 
palms. (17) 

In effecting a classification of many objects and kinds, 
we must first lay down proper primary and subordinate 
principles, then arrange the objects according to the dic- 
tates of our primary principle, then subdivide every di- 
vision, according to the requirements of our most gener- 
al subordinate principle, and so on, till we come to the 
lowest subdivision. 

When we have to class a newly discovered or invent- 
ed object in its proper place, we must ascertain the di- 
vision to which it properly belongs, from its classic, or- 
defic, generic, and specific characteristics, or those which 
distinguish the class, order, genus', or species from its co- 
ordinate divisions. We begin with those of the highest 
division and proceed gradually to those of the lowest, 
arrange the object accordingly, and distinguish it by a 
suitable name. Thus, if we had just discovered the musk 
ox of Arctic America, the first glance would show that it 
is of the mammal class, while its horns and teeth charac- 
terized it as of the ruminant order: but its generic char- 
acter is not so easily determined. Its horns and general 
character indicate that it is an ox, while its long, woolly 
hair, its short legs, its nose and its face, ally it to the 
sheep tribe. Hence it is classed as an intermediate ge- 
nus, under the term Ovibos (sheep-ox), while the species 
is designated Moschatus (musky), from its rank musky 
smell. 

In effecting a physical classification of objects, we first 
select and arrange together those which exhibit the char- 
acteristic marks of the various divisions immediately be- 
low that to which they all belong, and then subdivide 
the groups thus formed, by placing together, apart from 
the rest, all those objects which possess the characteris- 
tics of the various groups of the next lower subdivision, 
and so on, till we arrive at the lowest. 

Wherever it is found that our principles are objection- 
able, because they fail to effect the desired result, we 
should modify or alter them, so as to remove the difficul- 
ty, by which means we may gradually arrive at perfect 



Sec. 2.] Prejudices. 245 

principles. Thus, if a librarian attempts to an*ange all 
his books on the primary principle that those treating of 
the various subjects were to be separated, he would soon 
find that his principle is objectionable, because many- 
books treat of different subjects. This would lead him 
to the better primary principle, that books which treated 
of several distinct subjects, were to be separated from 
such as treated of only one subject ; and then he could 
properly apply his original principle to the latter. 

Prejudices may injuriously affect this subject, as well 
as every other, because we are strongly tempted to place 
a favorite individual, and especially ourselves, in a class 
better than that to which he really belongs, and to re- 
verse this error, in the case of a being that we dislike. 
The proper course is, to ascertain the individual's real 
characteristics, and then set him down in that class to 
which he is unequivocally attributed by the proper prin- 
ciple. 



246 



CLASSIFICATION. 



[ClIAP. XTV. 



CHAPTER XIV. 



TABULAE VIEW OF THE iTEAXS OF ACQUIRING KNOWL- 
EDGE. 

I. Necessary and Universal Truths are learned by 

(1.) Truisms. 

(2.) Self-evident properties of Time and Space. 

(3.) " Abstract Quantity. 

(4.) " Substantial Beings. 

(5.) " Relations of Things. 

f(l.) The necessary properties of Space and 

Time, which are not self-evident. 

(2.) The necessary properties of Abstract 

Quantity, which are not self-evident. 

(3.) The necessary properties of Substantial 

Beings, which are not self-evident. 
(4.) The necessary properties or Relations 
of Things, which are not self-evident. 



Direct Intuition, 
including 



All the intel- j 

lectnal fac- I • •. 

i • -j j inclu 
ulties,aided > ,. 

by signs and i s 

symbols, J . 



»1 



2. Comprehension, Intui- 
tion, and Memor 
often aided by Testi 
mony and numerous 
external appliances, 



IT. Particular Contingent Truths are known by 

,' (1.) Perceptions. 
1. Direct Comprehension, including I (2.) Sensations. 

our present j (3.) Ideas and phantasms. 

I (4.) Emotions and desires. 
'(1.) Our own existence. 
(2.) That of other substantial 
beings around us. 
whence J (3.) The obvious properties of 
we know ] us and them. 

(4.) Our own past experience. 

(5.) That of others, including 

History and Biography. 

LIT. General Contingent Truths are known by 

1. Comprehension and Abstraction, whence we learn empiricisms re- 

garding the present. 

2. Comprehension, Abstraction, and Memory, aided by audible and 

visible signs, including Testimony, whence we know empiricisms 
regarding the past. 

3. Comprehension, Abstraction, Memory, and Intuition, generally aid- 

ed bv signs and apparatus, whence we learn obvious inductions 
regarding the past, present, and future. 

4. All the intellectual faculties, aided as in the preceding case, whence 

we learn recondite inductions and inventive truths. 

TV. Hypothetical Truths and Probabilities are learn- 
ed by the same means as the third class. 



PART III. 

OF FALLACIES. 



CHAPTER XV. 

NATURE AND CLASSIFICATION OF FALLACIES. 

§ 1. Nature of Fallacies. — Definition and Operation of Fallacies. 
— Why they frequently produce Belief. — Their Number. — Two 
Evils resulting from Fallacies. 

A fallacy is, any thought, expression, or argument, 
which tends to produce erroneous belief. It has always 
some semblance of proving a certain conclusion, "with- 
out which it could have no such tendency ; and we are 
frequently liable to adopt the error, without ever sus- 
pecting its existence. When a fallacy is clearly exposed 
or understood, its worthlessness as a proof appears so 
glaring, that we are apt to think it could never impose 
on anybody ; yet, when presented in the disguised and 
indirect form in which fallacies usually come before the 
mind, it often produces conviction, especially when fa- 
vored by prejudices ; and it cannot sometimes be detect- 
ed without close attention and great care. 

The difficulty is frequently increased, and the recep- 
tion of the fallacy facilitated, by the argument's contain- 
ing a combination of fallacies, in which one conceals, and 
consequently strengthens, another, and its being believed 
by the party who propounded it, and who is consequent- 
ly sincere in his advocacy of it. We are also liable to 
overlook fallacies which originate wholly with ourselves, 
because we do not suspect their existence, and are un- 
willing to believe that we have been misled. Many fal- 
lacies, again, may be detected by a very brief close exam- 
ination of them ; yet, owing to ignorance of their nature, 
and attention not being called to the defect, no such ex- 
amination is ever made. 

Fallacies have no definite limit as to number ; and they 
admit of endless modifications and combinations, so that 
a complete enumeration or precise definition of every fal- 
lacy is impracticable : yet, when we understand the na- 
ture and operation of those which most usually occur, 
we need have little difficulty in detecting all others. 

Fallacies hide truth, and substitute positive error in 
L2 



250 Nature of Fallacies. [Chap. XV. 

its place. As conscious ignorance is preferable to delu- 
sion, it were better not to engage in the pursuit of truth 
at all, than to do so, and fall into error, which not only 
misleads us directly, but prevents further investigation, 
and leads to the rejection of every incompatible truth. 

§ 2. Classification of Fallacies. — Three Classes of Fallacies. — 
(1) Paralogisms. — (2) Sophisms. — (3) Aberrancies. — Universal de- 
fect in Fallacies. — Why these three include all possible Fallacies. 
— Their independence of each other. — What invalidates an Argu- 
ment. — Practical Application and Illustration. 

Fallacies may be divided into the three following 
classes, corresponding to the three parts of a syllogism. 

1. A comprehension exhibits the appearance of some- 
thing different from the reality, or something appears to 
be self-evident or known by satisfactory proof when it 
is neither ; and thus we are led to infer that we discern 
or learn something, which, in truth, we do not. This 
class we term paralogisms, or fallacies of primary as- 
sumption. A paralogism may, therefore, be defined a 
delusive representation, leading directly to an erroneous 
belief. 

2. Something is inferred from a premise which is not, 
in reality, implied in it. This class we term sophisms, 
or fallacies of intermediate reasoning. A sophism may, 
therefore, be defined a syllogism or argument in which 
the inference or conclusion is not implied in the premises. 

3. The actual conclusion is not the proposition which 
ought to have been proved, but one essentially different, 
which forms an aberrancy, or fallacy of irrelevancy. It 
is, therefore, an argument or syllogism, the conclusion 
cf which is not the question, or the conclusion which 
ought to have been proved, but one essentially different. 

There is a false inference in every fallacy : but in par- 
alogisms it regards primary assumptions — in sophisms, 
intermediate reasoning — and in aberrancies, a final con- 
clusion. Hence, the same fallacy which is a sophism 
when it is employed to prove a further inference, may 
become a paralogism when it is used in the final syllo- 
gism of an argument. 

The above three classes include all possible fallacies; 
for, if all our primary assumptions are sound, our infer- 
ences from them legitimate, and our final conclusions the 
very things to be established, there is evidently no pos- 



Sec. 2.] Classification or Fallacies. 251 

sibility of error. Hence all fallacies must regard our 
primary assumptions, our reasonings from these, or our 
final conclusions. 

Those three classes of fallacies are all distinct and in- 
dependent. We may reason correctly from unsound 
premises ; or we may reason sophistically from unobjec- 
tionable premises ; or both premises and reasoning may 
avail nothing, since they are beside the real question : 
and an argument is rendered worthless by involving any 
one of those fallacies. One material defect invalidates 
the whole, as much as if no part was sound. It may pos- 
sibly contain two or three kinds of fallacy : yet, in exam- 
ining its validity, if we find one fallacy, it is quite un- 
necessary to search for a second. 

If the premises require proof, and none is given, we 
need not search to see whether the conclusion is implied 
in them, Or whether it is relevant. The whole is like a 
fabric built on sand ; and it is not stable, however strong 
the superstructure. It is not requisite to show that the 
premises are false, in order to refute an argument based 
on them : it is sufficient to show that, for any thing which 
appears to the contrary, they may be false. If they are 
doubtful, an argument which, in order to be valid, re- 
quires that they must be known truths, is as worthless 
as if they had been proved to be false. 

If it appears that the conclusion is not implied in the 
premises, it is unnecessary to test their soundness, or the 
relevancy of the conclusion. Here the fabric has no 
strength in itself; and, therefore, the firmness of its 
foundation avails nothing. 

If the conclusion is irrelevant, all that precedes is tan- 
tamount to nothing : for here the fabric is erected on a 
wrong foundation; and, therefore, it leaves the place 
where it ought to have been built still vacant. 



252 Sources of Fallacies. [Chap. XVI. 



CHAPTER XVI. 

SOURCES OP FALLACIES, AND MEANS OP GUARDING AGAINST 
THEM. 

§ 1. Sources of Fallacies. — Twofold Source of Fallacies. — Intrin- 
sic Sources. — Extrinsic Sources. — Immediate extrinsic cause of 
all Fallacies. — How it operates. — Seven causes of Inattention, with 
Remarks. 

The sources of fallacies are either intrinsic or extrinsic. 
The former lie in the subject, and the latter in the inves- 
tigator. 

All intrinsic sources of fallacy lie in one thing's re- 
sembling another so much as to be readily mistaken for 
it, while they are materially different, or in two things 
differing so much that Ave are apt to think they differ 
altogether, while they are virtually alike, so far as con- 
cerns the matter in hand. 

The intrinsic source of paralogisms is found in a delu- 
sive representation, which is apt to lead directly to the 
inference that we know or learn something which, in 
fact, we do not. 

The intrinsic cause of sophisms lies in one thought or 
expression's being so like another as to be readily mis- 
taken for it, while the two are radically different, whence 
we are apt to infer that a premise implies an inference 
which, in reality, it does not. 

The intrinsic source of aberrancies consists in the ques- 
tion at issue bearing some resemblance to another^ which 
is essentially different, whence it is apt to be inferred 
that the former is proved, when the latter only may 
have been proved. (18) 

Inattention is the immediate extrinsic cause of all fal- 
lacies: for, if we carefully attend to a subject, we shall 
know whether the premises are sound, whether they im- 
ply the conclusion, and whether the one established is 
the right conclusion. Fallacious phenomena often lead 
to false inferences : yet the appearances are real ; and no 
false inferences are drawn regarding them, wherever we 
give them sufficient attention. 



Sec. 1.] Causes oe Inattention. 253 

Inattention operates by leading us, either to overlook 
something altogether, or to draw immaterial distinctions, 
or to overlook characteristic differences, so that we mis- 
take one thing for another. 

In order to secure attention, we must ascertain the 
causes of inattention, of which the following are the 
principal. 

1 . The painfulness of close and continued, attention. 
This generally requires a strong and unpleasant effort : 
for the mind naturally tends to run off from the point 
under consideration to something else, which it suggests, 
and which it is less irksome to contemplate, while we 
are glad to avoid the painful feeling of exhaustion which 
such attention produces. Hence investigation is often 
hurried ; and various points are considered inattentively, 
as the mind wanders from the subject, before we have 
obtained either an accurate or an extensive insight into it. 

2. The sacrifice of present enjoyment often involved in 
continued attention. The earnest investigator must oft- 
en deny himself many pleasures which are freely enjoyed 
by others, as when he sits in silence, pondering over dif- 
ficulties, or when he is busy amid objects offensive to his 
senses,' while his friends are enjoying the pleasures of 
social intercourse, or the beauties of external nature. 

The two preceding causes generally operate simulta- 
neously on the individual, and, owing to their combined 
influence, the attention often wanders from the subject ; 
things are viewed hui*riedly and inaccurately; conclu- 
sions are adopted or rejected without proper investiga- 
tion ; and erroneous opinions result. 

3. Thinking of too many things at once. The atten- 
tion to any point becomes less and less, as the number 
of objects to which it is directed increases, supposing 
that none of them excite it strongly. Hence a person 
who thinks at once of several things, each of which re- 
quires close attention, is very liable to err regarding one 
or more of them. 

4. Strong sensations or perceptions. When a person 
endures acute pain, or has his attention forced on some 
strong perception, such as the discharge of a gun very 
near him, it is generally impossible to attend either close- 
ly or continuously to the matter in hand. Even moder- 
ate pain, if continuous, such as hunger and thirst, distract 
the attention, in ordinary circumstances, to such a de- 



254 Sources of Fallacies. [Ciiap. XVI. 

gree as to render the investigation quite unreliable. 
Strong pleasing sensations are equally unfavorable to the 
discovery of truth. A person whose ear is delighted 
with sweet music, or who views a very striking and beau- 
tiful scene, for the first time, need not hope to solve any 
difficult problem. In all such cases, the attention is 
drawn so powerfully to the apprehension, that we can- 
not examine another subject with any degree of care. 

5. Obticseness of the faculties, arising from fatigue, 
disorder, or some permanent defect. A person who is 
sleepy, or suffering under the influence of a narcotic 
drug, cannot pay close attention to anything which does 
not produce unusually strong feelings ; and the same re- 
mark applies to one who is prostrated by strong previ- 
ous excitement, or whose faculties are naturally very dull 
and torpid. 

6. Strong emotions, unconnected with the subject of in- 
vestigation. These distract the attention quite as much 
as strong apprehensions, and operate precisely in the 
same way. A man who is excited with wrath, or in a 
paroxysm of joy, is as unfit for investigation as if he were 
laboring under a burning fever, although his passion 
should be entirely unconnected with the subject of in- 
quiry. 

7. Prejudices, or emotions connected with the subject 
of investigation. So much often depends on the conclu- 
sion at which we may arrive, that strong feelings are ex- 
cited, which mislead us like other emotions. But here 
we are less apt to be sensible of their influence, while, at 
the same time, this is more constant, and not so easily 
avoided. Hence prejudices are the most fertile of all 
sources of error. 

§ 2. Of Prejudices. — Modes in which Prejudices operate.— Causes 
of their power. — In what cases they exist. — Five classes of Preju- 
dices, with Kemarks. — Combination of Prejudices. — Source of the 
power of Error. — Why we readily take for granted what we are 
taught. 

While prejudices distract the attention, like other emo- 
tions, they also tend to withdraw it from whatever leads 
to a disagreeable conclusion, and to concentrate it on 
those of a contrary kind, because we naturally turn away 
from painful feelings, and fix the attention on such as are 
agreeable, just as we turn from loathsome sights or odors, 






Sec. 2.] Prejudices. 255 

to such as are pleasant. Hence we are disposed, not only 
to overlook that side of the subject which makes against 
the conclusion we desire to be true, but also to view the 
other side as being brighter or stronger than the reality, 
because we overlook all the weak and hostile parts of it, 
and confine our attention to the others. 

The case of persons who take a more gloomy view of 
a subject than truth warrants, is no exception to this re- 
rnai'k : for security against some anticipated evil, or a 
deliverance from present pain, appears to them extreme- 
ly desirable, as the amount of evil is generally exagger- 
ated, from some mistaken opinion, or a timid and over- 
sensitive disposition. 

The attention is thus apt to be confined to those things 
which make either for or against the conclusion, while 
the rest of the subject is either wholly overlooked, or not 
considered with any degree of care. Hence futile dis- 
tinctions are taken for essential differences, while the lat- 
ter are either overlooked or treated as immaterial, and 
one thing is mistaken for another, of a widely different 
character, so that fallacious arguments are adopted as 
conclusive, while irrefragable proofs are rejected as un- 
satisfactory. 

Not unfrequently the Imagination rivets the error, by 
drawing unfaithful pictures, which are taken to be cor- 
rect, because the attention is so absorbed that their true 
character is not perceived. The bright parts are exag- 
gerated, because their worse aspects are overlooked, and 
imaginary excellence is superadded, while the dark parts 
are equally misrepresented, because we do not attend to 
their better aspects, and we attribute to them imaginaiy 
evils. At the same time the emotions excited prevent 
us from adverting to the fact that the picture is only 
imaginary, and lacks proof. 

The influence of prejudices is very apt to escape our 
notice, because they operate rapidly, quietly, and without 
any noticeable effort, whence their power is increased, 
because it is unperceived, or even unsuspected. Thus 
the Judgement becomes the dupe of the feelings, and 
we unconsciously form very false opinions, under the 
partial and erroneous views of a subject thus produced. 
Such opinions are often held with great tenacity, because 
we are quite unaware of the deception which we prac- 
tice upon ourselves; and they are more numerous than 



256 Sources of Fallacies. [Chap. XVI. 

the fallacies arising from other emotions, because preju- 
dices operate secretly and incessantly. Every important 
subject generally excites some prejudice, which arises 
quietly and operates, in a great measure, undiscernibly, 
because there is no palpable indication of its presence, 
whereas a man under the influence of violent wrath, or 
deep grief, is apt to allow his emotion to subside, before 
he undertakes to investigate any subject of consequence ; 
and he has, at all events, a distinct knowledge of the dis- 
advantage under which he labors. 

The influence of prejudices is strengthened by our be- 
ing very unwilling to believe its existence, or to examine 
their operation aright. It is mortifying to our self-es- 
teem to think that we have been deceived by our wish- 
es; nor is it easy to understand how this happens. 
Hence many never acquire that knowledge of the na- 
ture and operation of prejudices which is requisite to 
guard us fully against their influence. 

Prejudice exists wherever strong emotions are excited 
by the contemplation of the results at which we may ar- 
rive : for these feelings excite a strong desire that the 
proposition under consideration should be true or false, 
owing to our belief regarding the good or evil connected 
with the alternatives. 

As all prejudices operate in the same way, and their 
number is indefinitely great, a complete enumeration of 
them is neither desirable nor practicable. The following 
are the most common. 

1. Prejudices of self-love in general. Every one nec- 
essarily desires his own welfare, and is, therefore, prone 
to believe whatever tends towards that object, and un- 
willing to believe the reverse. Hence the readiness with 
which youth expects a happy manhood, and the latter 
believes that visionary projects are highly eligible. 
Hence, also, the readiness with which many listen to 
flattery, or fish for applause, or foster pride, by believing 
that they and their kindred are superior to others. 
Hence our unwillingness to listen to reproof and bitter 
truths, and our readiness to believe agreeable falsehoods, 
to interpret the language of others so as to square with 
our views and wishes, and to accept or reject their testi- 
monies, according as it is agreeable or the reverse. 
Hence we are apt to form too high an opinion of our- 
selves and what concerns us, and too low an estimate of 



Sec. 2.] Prejudices. 257 

others. Hence, also, the undue value we often attach to 
what affects our own welfare, and the underestimate we 
make of what concerns our neighbour's ; and hence our 
unwillingness to believe that our own characters, views, 
opinions and pi-ospects are bad. 

2. Prejudices of the riding desire. A great portion of 
mankind consider some particular thing much more val- 
uable than any other good; and hence they desire it 
with corresponding earnestness and constancy. Every- 
thing is viewed under the influence of this prejudice ; 
and nothing is patiently considered which tends to prove 
that the object of pursuit is unworthy of such anxieties 
and toils, or that there is something else of much more 
consequence. A miser will not consider the evils inci- 
dent to an inordinate pursuit of gain ; and a vain person 
is unwilling to believe that his flatterers are either mock- 
ers or designing knaves, although this may be very ap- 
parent to others. The man who makes reputation his 
chief good, rejects all arguments to prove that he is pur- 
suing a shadow ; and the sensualist will listen to nothing 
which goes to prove that there is anything within his 
reach of vastly more importance than sensual gratifica- 
tions. 

3. Prejudices arising from the love of present ease or 
enjoyment, and an aversion to present toil or suffering. 
What is present, or in immediate view, is easily appre- 
ciated, and if it be deemed of much consequence, it usual- 
ly excites a strong desire to secure or avoid it. But the 
case is far otherwise with the distant future. This gen- 
erally requires careful consideration, in order to be prop- 
erly estimated, because remote objects appear indistinct 
and smaller than the reality to mental, as they do to ocu- 
lar, vision ; and, in many instances, the real character of 
the future can be ascertained only by means of continued 
and painful efforts, which all dislike, and which an ex- 
amination of the present does not involve. At the same 
time the attention is naturally drawn first to that which 
is near, as being the most striking, and often the most 
urgent ; and the anticipation of speedy pleasure or pain 
withdraws it from a careful consideration of the future, 
which is also less vividly pictured by Conception. Hence, 
when the choice lay between the present and the future, 
mankind have frequently preferred the former, even 
where the latter was incomparably more important. 



258 Sources of Fallacies. [Chap. XVI. 

From this prejudice originates the practice of taking 
up a subject, and studying it only till its novelty has 
ceased to tickle the fancy, when it gives place to some 
other, which soon makes way for a third, and so to the 
end of the cycle. In this way many have become proud 
of their attainments, when, in truth, they never mastered 
the rudiments of a single important study. A similar 
effect of this prejudice is, the common predilection for 
such methods as profess to furnish a short and easy road 
to knowledge, and the dislike for such as require a great 
degree of labor, and also the predilection for those stud- 
ies which either please at the time or promise the speedy 
gratification of some favorite desire, in preference to 
those of a contrary character, though the latter are gen- 
erally by far the most important. 

From the same source has originated many false 
maxims, such as that all valuable truth is easily acquired, 
that whatever is unknown must be of little value, that our 
faculties are very blind and weak, that we can know very 
little at the best, and that all real knowledge is very 
simple. Although it is easily seen that all such dogmas 
are false, yet, with their aid, many contrive to keep 
themselves very ignorant of various truths which it deep- 
ly concerns them to know, while they adopt errors in 
their stead, without ever suspecting that all is not right. 

Another instance of the effects of this prejudice is, the 
dislike which men swayed by evil desires or groveling 
appetites bear to true religion and sound morality. These 
militate against their present enjoyments. Hence they 
generally fly to religious scepticism, fanaticism, or super- 
stition, any of which is more conformable to their wishes 
than truth; and consequently the same person often 
swings repeatedly from one to another of these errors. 

Another frequent instance is, the devotion to that 
course which promises most money. This commands 
various immediate pleasures, while it secures men against 
various present pains, and hence the avidity with which 
it has been sought by the countless votaries of Mammon. 
The preference of sensual to mental gratifications is an 
equally common instance. The former can be enjoyed 
without any previous study or self-denial. 

From this prejudice also springs that fondness which 
many show, for adhering uniformly to general rules or 
modes of acting, however requisite modifications or de- 



Sec. 2.] Prejudices. 259 

viations may be, in certain instances. Hence they fre- 
quently run from one extreme to another. If they get 
into serious trouble, from following their usual course, 
they are apt to discard all rules ; and if they find that 
some of their opinions are not wholly true, they will 
probably reject them altogether, and adopt the contrary, 
which may be more erroneous than the former. 

4. Prejudices of education and profession. The ha- 
bitual consideration of some objects, or parts of a sub- 
ject, to the exclusion of others, tends to produce very 
erroneous opinions, since we attach little importance to 
that of which we are ignorant. Hence those objects 
often excite emotions and desires extremely dispropor- 
tionate to their real importance. The subjects which we 
have been taught in youth, and those things with which 
our vocation makes us familiar, are frequently viewed 
through this distorting medium, and seem very different 
from the reality, while we test everything by that with 
which we are familiar, however inapplicable. Every 
bigot thinks that saving truth is found with his creed 
alone : the artisan is apt to think that his art is the most 
important, ingenious or beautiful in the world : the mer- 
chant is inclined to apply figures to everything, and to 
estimate the character and prosperity of a nation by its 
exports and imports ; and the mathematician sometimes 
attempts to improve mental science by very rigid argu- 
ments, based on specious, but inaccurate, definitions, and 
plausible, but erroneous, assumptions, leading to irrele- 
vant conclusions. So every nation and class are apt to 
think more favorably of their own institutions, laws, cus- 
toms, and manners than would be warranted by an im- 
partial judgement. 

5. Prejudices of ' association. It often happens that 
things are associated in our minds with excellences or 
defects with which they have no necessary and uniform 
connection, whence the contemplation of them excites 
emotions which properly belong to the latter, but which 
are referred to the former, as their cause. Consequently 
they are judged according to those emotions, and very 
erroneous opinions are formed regarding their real na- 
ture. A person, for instance, flatters those whom he ad- 
dresses. This pleases them ; and they attribute the j>Ieas- 
ure to his superior judgement, the excellence of his argu- 
ments, or the goodness of his cause. Hence flattery has 



260 Sources op Fallacies. [Chap. XVI. 

ever been a powerful instrument of deception. One man 
has a repulsive aspect, and hence a prejudice against 
his sentiments : another appears benevolent, and hence a 
prejudice in favor of his opinions. 

This class of prejudices has produced much evil 
throughout the world. The heathen has often clung to 
his gods, and rejected the clearest proofs that they are 
only imaginary monsters, because their worship was as- 
sociated with his domestic joys, and they did not pro- 
hibit wicked practices to which he was strongly attach- 
ed. So the child, whose vicious propensities were curb- 
ed by his parents and teachers, has often been prejudiced, 
on that account, against the truths which they inculca- 
ted, while another, whose wicked inclinations were free- 
ly indulged, was strongly prejudiced in favor of the false 
teachings of those who so indulged him. Men are thus 
very apt to be prejudiced in favor of false opinions which 
accord with their vices ; and here lies the power of error. 

Prejudices often derive force from the combination of 
several, to produce the same result. A man, for instance, 
is strongly prejudiced in favor of his own views or opin- 
ions, because it is humiliating to think that he has been 
mistaken ; he has been so taught by his parents or teach- 
ers, whom he venerates ; if he should be in error, he must 
undergo the labor of re-examination ; and possibly he 
may arrive at conclusions repugnant to his ruling de- 
sires, and tending to render him less acceptable to per- 
sons whose good opinion he wishes to possess. 

From such sources originates the common practice of 
taking for true what we have been taught or have hith- 
erto believed, and looking to the mere opinions of others, 
instead of searching for conclusive proof. It is so much 
more pleasant and easy to accept current opinions, which 
tally with our wishes, and to compare and criticise writ- 
ten statements, than to investigate the subject properly 
for ourselves, that we need not wonder a large portion 
of mankind have adopted, from the earliest times, error 
which a very moderate degree of independent and care- 
ful observation and reasoning would have completely ex- 
ploded. 

§ 3. Means op avoiding Fallacies. — Requisites in order to avoid 
Fallacies. — Means of obviating the influence of Prejudices. — Two 
important means of avoiding Error. — Why Truth is often under- 
valued. — Consequences. — Proper Course. — Dangerous Practice. — 



Sec. 3.] Means op Avoiding them. 263 

Evil results of one fundamental Error, and of nhey will readily 
— How important Conclusions should be tested. — K ^ wherever 
guments which prove too much. — Means of counterac. - eau i rp ^ 
fects of Prejudices. — Refuting and proving Arguments. -H e 
tendency of the Mind, and consequent Caution. — Exception 1 . 611 
Common Error. 

In order to avoid erroneous opinions, we must atten- 
tively examine everything requisite to obtain a correct 
view of the subject under consideration ; and this re- 
quires that we avoid the various sources of inattention. 
Hence we should never study or investigate any subject 
while we are influenced by a feeling or perception so 
strong that we cannot readily concentrate our attention 
on any point at will, or while our faculties are blunted 
by sleepiness, languor, stupor, fatigue, exhaustion, or 
bodily disorder, so that we cannot pay close attention 
to the subject ; nor should any confidence be placed in 
conclusions formed under such circumstances. 

We should guard against strong apprehensions and 
emotions, by keeping at a distance from their various 
sources, such as exposure to great heat or cold, sensual 
habits, loud noises, and exciting scenes, conversation or 
reading. Sensual habits are particularly injurious, be- 
cause they produce unnaturally powerful appetites for 
particular indulgences, which greatly distract attention, 
and at tho#ame time cause a languid and irritable state 
of mind, very favorable to the adoption of error. . Pas- 
sions operate in the same way: but their influence is 
much less extensive, because they are much less perma- 
nent in their effects. 

We should also beware of having our attention dis- 
tracted by considering several things at once: and hence 
an investigation should be subdivided into parts, every 
one of which can be closely examined, and its character 
determined, without paying any attention to the rest, 
during its examination. 

No subject should ever be considered negligently or 
inattentively. If it does not deserve careful attention, 
it were better let alone: for otherwise we shall be apt 
to form a habit of inattentive examination, which will 
cleave to us in investigating the most important subjects. 

The principal means of obviating the influence of 
prejudices is, to study their mode of operating, once for 
all, until we see the inevitable consequences of yielding 



260 Source of Fallacies. [Chap. XVI. 

ever been a powe, to mark the nature and tendency of 
has a repulp'rejudices regarding the immediate subject 
his sentbnsideration, and to cherish the dispositions and 
preilcs requisite for proper study and investigation. If 
we allow our minds to be controlled by prejudice, the 
flood-gates of error are thrown open, and we readily 
adopt it instead of truth, without ever suspecting the de- 
ception. We should distinguish the question before us 
from those which prejudice leads us to substitute for it, 
and to examine it aright, on its own merits, regardless 
of the real or fancied consequences. 

It is frequently impossible to eradicate a prejudice: 
yet its mere existence need not jirevent us from adhering 
to all the principles of proper investigation : for where 
conclusive proof is fairly understood, it necessarily pro- 
duces conviction, however disagreeable the conclusion, 
as when a man hears very bad news, and the testimony 
leaves no room to doubt its truth, or opens his purse, 
thinking it contains money to pay a demand made on 
him, and finds it empty. Prejudice can mislead us only 
by withdrawing or distracting the attention : and, there- 
fore, if this can be sufficiently secured, the subject will 
be seen in its true light, whether pleasant or the reverse. 

"We shall be greatly aided in overcoming the influence 
of prejudice, by forming a proper estimate of the value 
of truth, and habituating ourselves to en dire a little 
present evil, for the sake of a great future good : for 
prejudices derive their force chiefly from the induce- 
ments which they hold out to sacrifice the long future 
for the present moment. The discovery of truth may 
hurt our feelings for a little while : but, like a surgical 
operation, it has a healing effect. 

Prejudices are often on the side of truth : but, even 
here, they are apt to act injuriously, by preventing a 
proper examination of the subject. Thus, they may pre- 
vent us from knowing the real grounds of our opinions, 
and the futility of plausible objections and counter argu- 
ments, so that when the advocates of error afterwards 
assail us with these weapons, we are liable to be much 
perplexed, if not permanently misled. 

A knowledge of the great value of truth and the vast 
importance of the future, forms one of the most import- 
ant means of avoiding error. Mankind do and suffer 
much for the sake of gain ; and, as truth is of incom- 



Sec. 3.] Means of Avoiding them. 263 

parably more importance than money, they will readily 
make much greater sacrifices for its attainment wherever 
they understand its worth, while those actually required 
are much less. The self-denial, toil and suffering often 
undergone for the sake of gold, greatly exceed anything 
which" the proper pursuit of truth demands, although, 
like every real good, it requires sacrifices. 

In order, however, to know the value of truth, it is 
often necessary to look steadily into the future ; and this 
is strongly opposed by the desire of immediate enjoy- 
ment, and the aversion to present toil or suffering. Hence 
truth is often exceedingly undervalued ; and men fly to 
false maxims or opinions, to justify themselves in neglect- 
ing to search for it aright. It is assumed, for instance, 
that all important truth is easily discovered; and then 
the dictates of prejudice, the illusions of the senses, or 
the deceptions of knavery, are received as truths that re- 
quire no further examination, and ought not to be doubt- 
ed. Or, it is assumed that nothing can be certainly 
known, and, therefore, it matters little what we believe. 

Errors of this kind should be carefully avoided : for 
they undermine the very foundations of knowledge. 
There is no more important requisite for right investiga- 
tion than correct views of its value ; and the absence of 
it is a most fruitful source of error. False maxims and 
opinions, such as those just adverted to, are so frequent- 
ly echoed from man to man, and chime in so exactly 
with our wishes, that they have imposed on the great 
majority of mankind, from the earliest times, and, by pre- 
venting due investigation, led them to adopt error in the 
place of truth. 

In order to understand any important subject coi'rect- 
ly, we must always labor on things which are intrinsic- 
ally uninviting, if not unpleasant, but which are inter- 
esting as necessary means to future results. We should 
beware of the childish practice of looking only at what 
is near, and overlooking all beyond as of little conse- 
quence : else we shall allow things comparatively trifling 
to set aside the consideration of the most momentous 
subjects, and resemble a man journeying on very import- 
ant business, who lost his object, by turning aside to 
gather flowers. Everything should be estimated at its 
real value, without making any distinction between the 
present and the future, since the former is incessantly 
vanishing and giving place to the latter. 



264 Sources of Fallacies. [Chap. XVI. 

Some are quite satisfied to believe like their friends ; 
and these, in their turn, think they are safe in imitating 
the former, when possibly all are equally in error, and 
they are mutually confirming each other in false opinions. 

The importance of care, at every step of our investi- 
gations, appears from the facts, that one error may lead 
to many others, as sure consequences, and that a mistake 
on a single point may mislead us regarding the whole 
subject. It is often impossible to foresee the future ef- 
fects of a certain conclusion ; and hence we are liable to 
attach little importance to points which may be of the 
utmost consequence. If a man radically err regarding 
the doctrines of causation and free agency, for example, 
all his opinions regarding God and duty will be little 
more than a tissue of errors, in which one fallacy sup- 
ports another ; and a man who believes that we cannot 
acquire any certain knowledge, will never be successful 
in its pursuit. 

Mere feebleness of intellect rather fosters ignorance 
than leads to positive error, since there is inaction, and 
not misdirected action. Hence idiots never adopt many 
errors which have been held by men of great abilities, 
into which they were led by prejudices and ill-regulated 
feelings. 

Every conclusion should be carefully traced, step by 
step, to its foundations ; and none should be admitted 
as true unless the proof is found conclusive. In cases of 
difficulty and importance, it is proper to write a synop- 
sis of the whole proof, from the primary premises to the 
conclusion, omitting all unessential matter, and laying 
down every part in its proper place. The synopsis should 
then be scrutinized till we know that we have carefully 
considered every part, and ascertained its true character. 

Fallacious arguments frequently pass for sound reason- 
ing, because they are interlarded with various illustra- 
tions and irrelevant matters : and, therefore, it is desir- 
able to separate the essential parts from the rest, and ex- 
hibit the argument in its naked and most concise form, 
when its true character can be generally ascertained by 
a little close attention to the exact nature and connection 
of its various parts. 

Wherever it is alleged that an argument proves too 
much, or that it leads to some false conclusion, we ought 
to examine the subject till we have certainly ascertained 



Sec. 3.] Means of Avoiding them. 265 

whether it does so or not. If it do, it is unsound. If it 
do not, we must not infer that it is conclusive, as it may 
possibly be refutable by other means ; but it should be 
tested by a proper examination. Men frequently allege 
that an argument which establishes a conclusion that 
conflicts with their wishes or opinions, proves too much 
when such is by no means the case. 

Where prejudices are possibly concerned, we should 
compare our own conclusions with those of persons of 
opposite prejudices, if such there be, and then examine 
and compare the arguments on each side, till we ascer- 
tain the source of any discrepancy which appears in the 
conclusions. In order to know that a conclusion is true, 
it is not sufficient that we are satisfied and firmly believe 
it is so : we must have the evidence of Consciousness, at 
every step, as was formerly stated ; and where we have 
obtained such evidence, the conclusions are no longer 
opinions, but cognitions. 

We should never slight an argument which professes 
to prove a disagreeable conclusion, or one that runs coun- 
ter to our prejudices. If we are inclined to do so, we 
should try whether we can refute it, or demonstrate its 
inconclusiveness beyond all possibility of error, a course 
which will sometimes show us that it is irrefragable. 
On the other hand, we should most rigidly test the 
soundness of arguments which prove a conclusion that 
we desire to be true, and not rest satisfied that it is con- 
clusive till there is no possible room for any fallacy. We 
shall thus be likely to escape the numerous errors into 
which we are liable to be led by prejudices. 

The usual tendency of the mind is, to believe too read- 
ily what it wishes to be true, and to disbelieve too read- 
ily what it wishes to be false. Hence we should be par- 
ticularly circumspect in examining proofs, in all cases of 
this kind. A person sometimes hesitates in believing 
conclusive evidence of an agreeable truth, or in rejecting 
similar proof of the falsity of a disagreeable proposition : 
but this is only an exception to the general rule, arising 
partly from the antecedent improbability of the fact, and 
partly from the confusion caused by the strong emotion 
excited. Consequently the disbelief generally disappears 
as soon as the feeling has subsided, and the matter is 
viewed more calmly. 

As the sources of fallacy are very numerous, some 
M 



266 Paralogisms. [Chap. XVII. 

have concluded that we can be positively certain of 
nothing. But the fact that we sometimes adopt errone- 
ous opinions, by no means proves that we cannot possess 
certain knowledge. A proposition which conforms to 
the criterions of truth, cannot be false, although we some- 
times admit those of a different character as true. Our 
liability to err should teach us caution in forming con- 
clusions, and distrust of our opinions on subjects that we 
have never properly examined : but it furnishes no good 
ground for scepticism regarding matters where no fal- 
lacy can exist. 



CHAPTER XVII. 

OF PARALOGISMS, OR FALLACIES OF PRIMARY ASSUMP- 
TION. 

§ 1. Paralogisms op Intuition. — Intuitional Assumption. — Intui- 
tional Kejection. — Sources of these Fallacies. — Test of Intuitions. 

Intuitional assumption is, assuming a proposition as a 
premise, on the ground that it is self-evident, when, in 
reality, it is not. 

Intuitional rejection occurs where a self-evident pre- 
mise is rejected, on the ground that it is untrue, or wants 
proof. 

The former of these paralogisms arises chiefly from 
mistaking very familiar propositions for intuitions, from 
a desire to extend the sphere of universal truths, or from 
a bias in favor of a conclusion which the supposed intui- 
tion tends to establish. We are disposed to assume as 
self-evident what we have always considered such, espe- 
cially where the proposition proves a favorite conclusion, 
or saves the labor of close and continued observation. 
Hence propositions have been taken for intuitions which 
are self-evidently impossible, such as that we see dis- 
tance. 

Intuitional rejection generally proceeds from the prop- 
osition's conflicting with some cherished belief, or its ap- 
pearing novel or strange. We are as much disposed to 
reject what militates against the truth of favorite opin- 
ions as we are inclined to receive, without due caution, 
things of a contrary character. Many persons, also, 



Sec. 2.] Test of Intuitions. 267 

make their own views the standai'd of truth, and unhesi- 
tatingly reject, as unworthy of being deemed self-evident, 
anything which never appeared to them in that light. 
Instances of this occur in the repeated rejection of some 
intuitions regarding volitions and motives. 

To determine whether a proposition is self-evident, we 
must ascertain exactly what it is, and then attentively 
consider the thing meant, apart from the words in which 
it may have been expressed. If it is self-evident, its 
truth will then appear clearly and irresistibly, accom- 
panied with a discernment that it cannot by possibility 
be false, and that its contradictory is an utter impossi- 
bility. The criterion of intuitions is, as the name im- 
plies, that the attentive mind discerns they are neces- 
sarily and universally true, and cannot possibly be false, 
in a single instance. 

The self-evident nature of intuitions is evinced by all 
persons believing and acting on such as are clearly 
brought under the notice of their understandings, how- 
ever much some may profess to repudiate them. When 
a strange event occurs, without any known cause, those 
who maintain that causes are not necessary antecedents 
of changes, believe there must be a cause, while there is 
no other evidence of this except intuition. Experience 
does not show that eveiy event has had a cause ; for we 
do not know by experience that many events ever had 
a cause ; and even if we did, this would not prove any- 
thing regarding the future. The experience of persons 
in the various zones, regarding the apparent positions 
and the risings and settings of the heavenly bodies, are 
uniform, and yet quite different from their neighbours'. 

§ 2. Paralogisms of Assuming what is attempted to be proved. 
— Nature of these Fallacies. — (1) Assuming the Question. — Its 
Criterion. — (2) Reasoning in a Circle. — Its Criterion. — Origin of 
this class of Fallacies. 

In this class of fallacies, something which requires 
proof is assumed as a primary premise, while it is either 
virtually identical with the conclusion or is inferred from 
it, although the reasoning subsequent to the assumption 
may be quite valid. It includes the two following fal- 
lacies. 

1. Assuming (termed also begging) the question is, 
where we assume, as a primary premise, a proposition 



268 Paralogisms. [Chap. XVII. 

which requires proof, and which is virtually identical 
with the conclusion, although it may be differently ex- 
pressed. 

The criterion of this fallacy is, not merely the identity 
of the primary premise with the conclusion, but also that 
it requires proof, which is not given : for, if the primary 
premise requires no proof, there can be no fallacy of pri- 
mary assumption. Nor would the argument always be 
useless, since we may rightly assume the primary premise 
without seeing that it is, in effect, identical with the con- 
clusion, because the latter is differently expressed. A 
person often admits a proposition when it is expressed 
in one form, while he will deny it under another form. 

Instances of this fallacy occur in those cases where 
the premise is only the conclusion expressed in learned 
phrase, as where it is attempted to be proved that we 
ought to do a thing, on the assumption that we are un- 
der a moral obligation to do so, or that a man must be 
honest, since his conduct is always guided by principles 
of moral rectitude, or that a proposed law is good, since 
it will ameliorate the condition of the people, or that a 
politician cherishes no selfish views, since he is a disin- 
terested patriot, or that our views are right, since they 
are orthodox, and our opponents wrong, since they are 
heterodox. 

2. Reasoning in a circle (termed also the vicious cir- 
cle) is, where we either assume, as a primary premise, an 
inference from the conclusion and provable only by means 
of it, or attempt to deduce our first assumption from the 
conclusion inferred from it. In the former case, we first 
assume the inference, and then attempt to deduce the 
conclusion from it, while, in reality, the assumption re- 
quires proof, and can be proved only by means of the 
conclusion which it is employed to establish. In the lat- 
ter case, the conclusion is first proved by means of the 
premise, and the latter is then proved by means of the 
former. Both processes may be compared to an attempt 
to make the top of a house serve for its foundation. 

The criterion of this fallacy is, that something is as- 
sumed which requires to be proved by means of the con- 
clusion inferred from it. A frequent instance of it is, 
assuming a proposition generally, and then attempting 
to prove a particular case of it, by means of this assump- 
tion, when, in fact, the former assumption requires proof, 



Sec. 3.] Miscomprehension. 269 

which cannot be given otherwise than by means of the 
latter. It is assumed, for instance, that all men are mor- 
tal, and from this it is very easy to prove that A, B, or 
C is mortal. The principal difficulty lies in proving the 
assumption, which cannot be rigidly done at all, and 
which can be even proved to hold true generally only by 
assuming that some men are mortal. 

Another common instance is, where we take the word 
of a stranger, or a person suspected of being a liar, for 
his own integrity or veracity, or where one man's verac- 
ity is vouched by an unknown neighbour, and the man 
himself then vouches for the latter' s veracity. This has 
often been done, where all the parties were rascals, col- 
leagued with each other. 

Both these kinds of paralogism are frequently derived 
from false systems of philosophy or science : but they 
may also proceed from inattention in our own investiga- 
tions, in which we should guard against them, by attend- 
ing closely to the nature of our primary assumptions. 

§ 3. Pakalogisms of Comprehension. — (1) Miscomprehension. — 
(2) Incomprehension. — Influence of Intuitional Assumptions. 

1. Miscomprehension occurs where, owing to a want 
of due care and attention, we overlook or mistake char- 
acteristic marks and distinctions, whence we mistake one 
thing for another, or attribute to a subject something 
which does not, in reality, belong to it. A common in- 
stance of it is, where we attribute to one thing what re- 
ally belongs to another, with which it is associated, as 
when we erroneously fancy that certain forms and colors 
are beautiful because they are associated with something 
that is so, or think that the appearance of a person who 
has wounded our feelings is disagreeable, when it is the 
reverse, or that some insipid substance has an agreeable 
taste because it is fragrant. In the same way we some- 
times falsely attribute a certain character to a person, 
because there is something in his dress or appearance 
which we have erroneously associated with that charac- 
ter. Another common instance is, where we mistake one 
person for another, because we have not sufficiently at- 
tended to their distinctive differences. 

Strong emotions, especially when the organs are unfa- 
vorably situated, often produce this fallacy. A timid 
man, in a lonely forest at night, is very apt to take every 



270 Paralogisms. [Chap. XVII. 

black log for a bear, and every gray stone for a wolf. 
His fear causes vivid ideas of these animals, to which the 
things apprehended afford a basis of reality. So, when a 
person is very anxious to see a particular thing, or when 
it is suggested to him by others, a vivid similitude of it 
arises before his mind, and if there is anything visible to 
Avhich it bears the least resemblance, on which it can be 
superinduced, he blends the two objects, and readily be- 
lieves that he perceives the prototype of the similitude. 
It is thus that a man in a dim light sometimes thinks he 
sees various objects, when he perceives only things which 
somewhat resemble them. 

2. Incomprehension occurs where the whole of a sub- 
ject does not present itself to our view at once, but we 
discern only a part, and then assume that we have com- 
prehended the whole. We should remember that many 
facts may often be observed, which tend to prove a cer- 
tain conclusion, while possibly more may be found on the 
other side, which are very apt to be overlooked, when 
they oppugn some favorite opinion. The particular facts 
overlooked depend greatly on the individual's views and 
feelings, so that one overlooks the very things which an- 
other observes, and the latter overlooks all that the for- 
mer observes. 

A common instance of this fallacy is, where one thing 
is assumed to be a sure sign of another as uniform ante- 
cedent, concomitant, or consequent, when farther observ- 
ation would show that it is no such thing. Many super- 
stitious opinions originate in this way, such as the belief 
in omens, prodigies, lucky and unlucky days, places, and 
persons, dreams, fortune-telling, and the power of charms 
and incantations, although, in producing these results, 
the paralogism is generally combined with the sophisms 
of causation and generalization. 

In cases of this kind the instances which favor the con- 
clusion are carefully noted and remembered, while the 
other, and much more numerous, class, are either wholly 
overlooked or forgotten. When a quack descants on the 
supposed cures alleged to have been effected by his nos- 
trum, he says nothing of the much greater number of 
cases in which no benefit was derived from it, or it even 
produced serious evil. 

Another common case of this paralogism is, assuming 
that a few individuals of a class which we may have seen 



Sec. 4.] Illusive Sign. 271 

or known, are fair specimens of the whole, when there is 
no proof of this, and the fact may possibly be the reverse. 
Some travelers describe the character of a foreign nation, 
when, in truth, they never saw one of them in his ordi- 
nary mode of life, except innkeepers and their servants. 
So people have not unfrequently formed an erroneous 
opinion of mankind at large, from the general character 
of their friends and acquaintances. 

Another frequent instance is, assuming that the mode 
of effecting a certain end, with which we are familiar, is 
the only one, or at least the best, whereas several better 
ways may be known to others. 

Another common case is, where a person thinks he 
can safely afford to purchase several things,' because he 
can purchase any one of them without inconvenience. 
He never considers the result of purchasing the whole 
of them, but while he thinks of some, he overlooks the 
rest. 

Fallacies of comprehension are greatly fostered by in- 
tuitional assumptions, which often lead us to think, either 
that no observation is requisite, or that we have already 
comprehended enough, when the case may be far other- 
wise. For we are not disposed to seek for proofs of 
what we deem self-evident, nor to search for further 
proof where we are already satisfied, though without any 
good ground. 

§ 4. Paralogisms of Signs. — (1) Illusive Sign. — Its various Sources. 
— Its Character and Effects. — (2) Non-interpretation of Signs. — 
Frequent Combinations. 

Where a phenomenon is presented to our observation 
which appears, and which we assume, to signify some- 
thing which, in reality, it does not, we fall into the paral- 
ogism of illusive sign. It differs from those of compre- 
hension in our being misled solely by drawing a false in- 
ference, and the observation not being necessarily either 
careless or defective, though, in fact, it often is so. 
When we view a statue or a scarecrow, and take it for 
a living person, or when we look at the images produced 
on a screen by the magic lantern, and take them for real 
pictures, or when we have ringing sounds in our ears, 
and attribute them to some external source, we appre- 
hend the phenomena as they actually are, and we are 
misled solely by drawing erroneous inferences. So cer- 



272 Paralogisms. [Chap. XVII. 

tain symptoms are often inferred to indicate a particular 
disease, when, in reality, they do not, because they equal- 
ly accompany several other disorders. Yet the symp- 
toms may be observed with perfect accuracy, and it may 
be quite true that they always accompany the disease 
which they are erroneously believed to indicate. 

We readily fall into this fallacy when the organs of 
apprehension are diseased or defective. When the optic 
nerves are inflamed, the ideas of objects of sight some- 
times acquire unusual vividness ; and hence they are mis- 
taken for actual aj:>prehensions. In such cases, the phe- 
nomena are attributed to the causes which usually pro- 
duce similar phenomena, as these most readily occur to 
our minds. 

Prejudices sometimes produce this fallacy, even where 
there isoo organic or external difliculty. Thus, we are 
apt to infer that one whom we strongly dislike, is a bad 
man, because he exhibits some indication which leads to 
that conclusion, though it may really prove no such thing, 
and there may be positive proof to the contrary. On 
the other hand, we are very ready to infer that those we 
like are penitent, moral or intelligent, because they have 
done something which faintly indicates such an infer- 
ence, when there may be clear evidence of the reverse. 

To this paralogism belongs a host of common errors 
regarding the condition and character of others. A 
bashful man is often assumed to lack abilities or knowl- 
edge, while one who exhibits assurance is taken to be a 
man of talents and intelligence. A fine dress and equip- 
age have sometimes procured the credit of wealth, which 
was assumed to betoken happiness. Such errors are 
more common, because the thing assumed to be the sign 
is often caused by wilful imposition. It is often easy to 
borrow the language of the wise, the generous or the 
learned, while those addressed never suspect the imposi- 
tion, and consequently give the impostor credit for what 
really belongs to another. So the felon often counter- 
feits signs, to remove suspicion from himself, while he re- 
moves the real signs of his guilt. By such means, almost 
every virtue has been counterfeited, and every vice at- 
tempted to be concealed. 

This fallacy is of an insidious character, and very apt 
to escape detection, because the inferences are generally 
made with such rapidity that we overlook them, and sup- 






Sec. 4.] Non-interpretation op Signs, &c. 273 

pose that we apprehend what we only infer. Hence it 
is very apt to lead us into further errors, because we as- 
sume the false inference as an unquestionable compre- 
hension. 

2. Non-interpretation of signs is the converse of the 
preceding fallacy, and occurs where, owing to careless- 
ness or prejudices, we overlook the obvious and conclu- 
sive signification of a phenomenon presented to our view, 
and thus form an erroneous opinion of the subject. A 
common instance of it is, where we overlook the signifi- 
cation of certain actions performed by a person of whom 
we think favorably, and consequently form a better opin- 
ion of him than his real character warrants. Another 
similar instance is, when we form too low an opinion of 
one whom we dislike, because we misinterpret his ac- 
tions. 

Paralogisms of signs are often combined with those 
of comprehension. We obtain either an inaccurate or 
a partial view of what is presented to our observation, 
and we misinterpret what we do comprehend. Thus, 
we are apt to form erroneous opinions regarding the 
characters of nations, from that of a few persons, with 
whom we are not well acquainted, and whose conduct 
we misunderstand. So, if we extended our acquaintance 
with the man of supposed wealth, we might possibly find 
that what procured him the credit of wealth had never 
been paid for : and a further acquaintance with the man 
who counterfeited wisdom and virtue, might show him 
to be a silly knave. 

A common and serious instance of this compound fal- 
lacy occurs in the undue importance so frequently attach- 
ed to material interests and sensual enjoyments. Our 
apprehensions frequently shoAV us only the least import- 
ant side of the subject : but as this is seen at once, we 
are apt to look no further, while, in order to form a coi*- 
rect estimate, we must view the whole subject. This 
often requires toil and time, which we are unwilling to 
bestow, and self-denial, which we are unwilling to prac- 
tice. Hence men often form very erroneous opinions, 
and sacrifice a great good for one of comparatively no 
consequence. In order to form a proper judgement re- 
garding the comparative merits of different things or 
courses of action, we must obtain a full and fair view of 
every one of them ; and this may be prevented by our 
M 2 



274 Pabalogisms. [Ciiai\ XVII. 

prejudices wholly withdrawing the attention from sever- 
al points, so that we seriously err without ever suspect- 
ing the fallacy. 

§ 5. Paralogisms op Memory. — (1) Imaginary Apprehension. — Its 
Origin. — (2) False Association. — Its Character and Effects. — (3) 
Mistaking Ideas. — Its Character, and what it particularly affects. 
— (4) Forgetf ulness. — Distinction. 

1. The paralogism of imaginary apprehension consists 
in confounding the remembrance of apprehensions with 
that of conceptions, or mistaking a phantasm for an idea, 
whence we think that we apprehended what we only im- 
agined. We fall into this error only when our remem- 
brance of an occurrence is indistinct or defective : for, in 
other cases, the remembrance of the circumstances under 
which the conception was formed, will prevent any such 
mistakes. It occurs chiefly where some favorite concep- 
tion has been often considered, or originally absorbed 
the attention to such a degree that the impressions made 
by other things were faint, and consequently they have 
been forgotten, while the remembrance of the conception 
is, for the same reason, unusually vivid. It is owing to 
this fallacy that we hear some old men relating, with per- 
fect sincerity, that they saw or performed things which 
are purely imaginary. 

2. False association occurs where we mistake the time 
or place of apprehending a certain thing. This is owing 
chiefly to the idea of one apprehension becoming asso- 
ciated with that of another which was not contempora- 
neous with it, whence we infer that the two prototypes 
were simultaneous. Thus, we often believe that we saw 
an acquaintance at a particular time or place, when, in 
fact, we saw him at another time or elsewhere. Such 
mistakes are of frequent occurrence, and sometimes pro- 
duce serious consequences. 

3. Mistaking ideas is where the idea of one apprehen- 
sion is mistaken for that of another, owing to indistinct- 
ness or failure of remembrance, whence we believe that 
we apprehended a thing when we apprehended only 
something like it. This fallacy closely resembles that of 
miscomprehension, with which it is frequently combined, 
owing to our employing ideas as representatives of their 
prototypes. It affects number and quantity so much 
that little dependence can be placed on the remembrance 



Sec. 6.] Forgetfulness, &c. 27 5 

of a person of ordinary memory, regarding such things, 
except where his attention was particularly directed to 
them, at the time of apprehension. 

4. Forgetfulness is where we wholly forget something, 
and then assume that we never comprehended it. As 
we are liahle to such forgetfulness, the mere fact that we 
have no recollection of a thing, does not prove that we 
never comprehended it. Hence the only safe inference 
is, that we do not remember it, except it he such that we 
could not possibly forget it, if once comprehended. But 
this condition is often overlooked, and we think that we 
never comprehended, when we only forget. This fallacy 
is frequently combined with those of comprehension, as 
we are very apt to forget what we never rightly compre- 
hended. Instances of it occur where we undertake to 
do something in utter forgetfulness of the fact that we 
have already done it. Another similar instance is, when 
we believe that we never saw or said something which 
we really did, because we have no recollection of having 
done so. 

Memory generally retains the errors of original com- 
prehension. Thus, if we mistook the character of a thing 
when we saw it, without discovering our error, we shall 
continue to think that we saw what we took it to be, 
unless extraneous circumstances show that we were mis- 
taken : but neither the error nor the correction proceeds 
from the Memory ; and hence the consideration of them 
does not concern our present subject. 

§ 6. Intrinsic Paralogisms op Testimony. — Immaterial Distinc- 
tion. — Intrinsic and Extrinsic Paralogisms of Testimony. — (1) Am- 
biguous Expression. — Logomachies. — Equivocation. — Ambiguous 
Interrogation. — (2) Overlooking Conditions. — Eesults. — (3) As- 
suming Conditions. — (4) Obscure Expression. — Frequent source of 
this Fallacy. — Proper mode of dealing with it. — (5) Wrong Ex- 
pression. — (6) Falsehood. — Its Extent. — Erroneous Definitions. — 
(7) Suppressing Truth. — Where to be expected. — (8) Misrepresent- 
ing Comprehensions. — Its Extent. — (9) Misrepresenting Testimo- 
ny. — Where frequently employed. — Frequent Combinations. 

The question whether a witness believes his own state- 
ments or not, is of the utmost importance when we are 
considering his character : but it is generally of little or 
no consequence when we are inquiring whether they are 
true or false. The real sincerity of a witness who be- 
lieves his false statements, is quite as apt to mislead us 



276 Paralogisms. [Chap. XVII. 

as the mock sincerity of the liar ; and the belief or dis- 
belief of the witness is frequently no test of truth. Men 
often hear and relate truth without believing it; and they 
still more frequently utter falsehood unawares. Conse- 
quently we shall not here draw any distinction between 
conscious and unconscious errors. The character of the 
fallacy is generally unaffected by the belief or disbelief 
of the witness. 

Paralogisms of testimony are either intrinsic or ex- 
trinsic. The former comprise those where the testimo- 
ny is fallacious in itself: the latter include those which 
arise from our dealing with it fallaciously. We shall 
treat of the former in this, and of the latter, in the ensu- 
ing section. 

1. Expressions bear two or more different significa- 
tions, which are not distinguished, constituting the pa- 
ralogism of ambiguous expression. Thus, " testimony is 
fallacious," may signify all or only some testimony. AU, 
again, may signify either every one separately or the 
whole together / and some may denote a very few or a 
great many. So, " a scriptural custom" may signify sim- 
ply one which is frequently referred to in the Scriptures 
as existing, without any expression of approval; or it 
may signify one which is described as having the divine 
sanction, which is a very different thing. 

Many logomachies arise from overlooking the ambigu- 
ity of expressions. Such questions as "who was the 
greatest man that ever lived?" can be only disputes 
about words, till the parties have agreed in which of its 
numerous significations the word great is to be under- 
stood. In all such cases, there are, in reality, as many 
different questions as there are different significations of 
the expressions used. 

A common instance of this paralogism is, equivocation, 
or employing expressions which are true in one sense, 
but not in another, while the witness furnishes no indi- 
cation which of the two he would have us adopt. Some- 
times we cannot ascertain whether the language is fig- 
urative or literal, as when commendatory epithets are 
used, and they may possibly be ironical. This proceeds 
sometimes from a design to mislead, and at other times, 
from mere inattention or oversight. The ancient hea- 
then oracles, and the ambiguities purposely used in mak- 
ing contracts, furnish many instances of the former, and 
hasty compositions, of the latter. 



Sec. 6.] Fallacious Expressions. 211 

Sometimes the ambiguity assumes the form of an in- 
terrogation, which appears to admit of only one answer, 
but, in reality, admits of several, some true and some 
false. This form is distinguished as ambiguous interro- 
gation. It is frequently employed by witnesses who are 
unwilling to make a direct misstatement, which they at- 
tempt to avoid by an apparently candid appeal to the in- 
terrogator, as if the answer sought must be obvious to 
himself. The fallacy lies in the ambiguity of the ques- 
tion, and is to be avoided by ascertaining which of the 
several significations is meant. 

2. Expressions which are true only on certain condi- 
tions, are stated as if they were true absolutely, forming 
the paralogism of overlooking conditio?is. When it is 
said that " a man can live without eating on Saturday," 
this may be true if he did not fast before, but very false, 
if he has fasted during the previous fortnight. This pa- 
ralogism is one of the principal means of riveting the 
numerous errors arising from partial views of a subject. 
The language employed may directly express nothing 
but what is strictly true ; yet it naturally implies some- 
thing which is false. An ancient author might say: 
" the Sun appears in the south at noon, in every part of 
the known world," and the statement would be strictly 
true ; but the same expression is quite false at the pres- 
ent day. 

3. Expressions which are true absolutely, are assumed 
to be true only on certain conditions, forming the paral- 
ogism of assuming conditions. A common instance of 
it is, where a man assumes that some substance, habit, 
or course of life, will not injure him, on account of his 
peculiar constitutional character, when, in fact, it inevi- 
tably injures every one, just as fire burns, or ice chills. 

4. The expressions are so obscure that it is impossible 
to ascertain their precise meaning, or whether they have 
any, forming the paralogism of obscure expression. A 
common instance of it is, using figurative language in 
such a manner that we cannot form any definite notion 
of its meaning, whence we are liable to misunderstand 
it. The proper course, in such cases, is, to attach no 
meaning whatever to the language: for otherwise we 
shall very probably attribute to it a meaning different 
from what was intended. 

5. Wrong expression is where a person employs words 



278 Paealogisms. [Ciiap. XVII. 

which may he sufficiently clear and precise, but yet con- 
vey a meaning different from what he intended. Some- 
times improper terms are employed : in other cases, they 
are unobjectionable, but they are wrongly arranged or 
constructed. Typographical blunders, and slips of the 
tongue, furnish numerous instances of both these forms. 

6. Falsehood is, where a person, either knowingly or 
otherwise, makes a statement which is substantially, if 
not wholly, untrue, with the expectation of being be- 
lieved. Many expressions are false, in their ordinary ac- 
ceptation, which do not come under this head, because 
the real meaning is well understood, as in the case of 
figures of speech ; but here the witness speaks with the 
intention of producing belief; and the difficulty general- 
ly lies in the fact that there is no clear indication of the 
misstatement. It is frequently believed, owing to the 
apparent veracity and sincerity of the witness, the small- 
ness of the temptation to depart from truth, or the indo- 
lence or prejudices of the party addressed. It is also 
of very common occurrence, because there are so many 
ways of being mistaken, and so many temptations to 
misrepresent, even where the witness is well aware of 
the truth. 

A pernicious instance of this paralogism is, false defi- 
nition. This is very apt to escape detection, owing to 
the ignorance of the party addressed, and the presump- 
tion that he who undertakes to give a formal definition 
of a thing, understands it well. As definitions affect 
fundamental points, errors of this kind are very apt to 
convey radically erroneous views of the whole subject. 

7. Supjyressiyig tntth is where an important part of the 
testimony, or of what was witnessed, is entirely omitted, 
or the facts are garbled, and the favorable or unfavora- 
ble alone stated. A frequent instance of it is, depicting 
a few individuals of a class as fair specimens of the whole, 
when, in reality, they are not. This may not be directly 
stated ; but things are represented so as to lead to that 
inference. Every large class generally contains persons 
of very different characters ; and it is easy to select a 
few that differ widely from the great majority, who alone 
determine the character of the class. By such means 
very different pictures may be exhibited of the same 
community, the one as much darker than the reality as 
the other is brighter. So, by selecting the good and bad 



Sec. 6.] Misrepresentation. 279 

qualities of an individual, two very erroneous exhibitions 
may be easily given of bis character, yet both containing 
some portion of truth, so that they are readily received 
as accurate by those who like them. 

8. Misrepresenting comprehensions occurs where the 
truth is either exaggerated, extenuated, or mixed with 
more or less of positive error, in a statement of what the 
witness personally observed or experienced. This is oft- 
en done by employing terms either weaker or stronger 
than truth requires. Many actions or characters may be 
viewed in a favorable or an unfavorable light, as several 
virtues border on corresponding vices; and language 
affords abundant means of* representing it under either 
aspect, so as to contain some portion of truth. 

Hence there is a boundless field for the exercise of this 
paralogism. Penurious selfishness may be dignified un- 
der the name of " a prudent regard to our own interests," 
while a proper degree of economy may be styled " nig- 
gardly parsimony." Indifference to the welfare of others 
often passes for " good nature," while one who warns us 
of serious danger, which we wish to overlook, is termed 
"an officious intermeddler," and a well-timed rebuke 
passes for " scolding." An action may be called " brave" 
or " rash" — " prudent" or " cowardly" — " energetic" or 
" severe" — " liberal" or " extravagant." Real sublimity 
may be termed " unmeaning rant," while bombast passes 
for "sublimity." Vapid declamation is termed "true 
oratory," while genuine eloquence is characterized as 
" tumid bombast." Ruling a nation with a rod of iron 
has sometimes been termed " administering the govern- 
ment with a strong hand," while inefficient imbecility 
was styled " mild and paternal sway." 

Instances of this fallacy occur in the justificatory or 
defensive statements of a party charged with having 
done something wrong ; and its influence may often be 
readily seen by comparing the narratives which two ad- 
verse parties give of the same occurrence. 

9. Misrepresenting testimony is, where reliable testi- 
mony is misrepresented, so as to corrupt it materially. 
This is done in various ways. Sometimes it is mistrans- 
lated; and the error often escapes detection, owing to 
the original being unknown or inaccessible to the party 
addressed. Sometimes it is misquoted, and various gar- 
bled passages are strung together, with some important 



280 Paralogisms. [Chap. XVII. 

additions or alterations, so as to convey a meaning very 
different from the original. At other times confident ref- 
erences are made to testimony, as proving a certain prop- 
osition 'which it does not prove, sometimes with the ex- 
pectation that it will never be consulted by the party 
addressed ; and the fallacy is occasionally masked by a 
bold statement that the testimony is clear and conclusive, 
"while possibly it may be all the other "way. 

This paralogism is of frequent occurrence in contro- 
versy. An ojjponent's views are misrepresented, and 
then follows a refutation of imaginary statements or opin- 
ions ; or the doctrines of a party are erroneously assumed 
to be the same as those of some person connected with 
it. Fallacies of this kind occur so frequently that little 
confidence can generally be placed in a professed contro- 
versialist's representations of an opponent's views, except 
where he quotes fairly from some unexceptionable au- 
thority ; and it is unsafe to assume that he does so, with- 
out proof. 

The two paralogisms of misrepresentation are most 
frequently couched in spoken or written language : but 
they are sometimes communicated by various other 
means, such as inaccurate maps or pictures, or by sounds 
and tastes or odors, which do not rightly represent what 
they profess to do, as if a man should present an apple, to 
give us a notion of the smell of a rose, or imitate the note 
of the raven, as a correct representation of the cuckoo's. 

Intrinsic fallacies of testimony are frequently combined 
with each other. Ambiguous, obscure or wrong expres- 
sions accompany and strengthen falsehood, suppression 
and misrepresentation, so that it is sometimes very diffi- 
cult to ascertain their true character. This can be done 
only by a close and careful application of the criterions 
of testimony, which frequently requires time and toil, 
while the adoption of the fallacy requires neither. Hence 
they have been a very frequent and powerful means of 
producing and perpetuating error. 

§ 7. Extrinsic Paralogisms of Testimony. — (1) Adopting a Mean. 
— Erroneous Assumption. — (2) Counting "Witnesses. — Relation of 
Numbers to Credibility. — (3) Credulity. — Why prevalent. — (4) 
Scepticism. — Its Origin and Operation. — (5) Overlooking Testi- 
mony. — Its Origin.— (6) Indiscrimination. — Why prevalent. — Fre- 
quent Combinations. 

1. Adopting a mean is, where there are contradictory 



Sec. V.] Abuses of Testimony. 281 

01* inconsistent testimonies, and we assume that the truth 
lies between the statements of the different parties, while 
it may be quite otherwise. It is so much easier to ap- 
portion the difference between conflicting testimonies 
than to ascertain their true character, that this fallacy is 
of frequent occurrence. 

Some persons generally assume, in all cases of this 
kind, where their prejudices are not concerned, that the 
truth lies somewhere between the assertions of the dif- 
ferent parties ; and they take it to be nearest to those of 
the one who speaks with most confidence, whereas it is 
often beyond the statements of either party, or wholly 
with one, and that the party who speaks with least con- 
fidence ; and we can never safely assume that it is inter- 
mediate without conclusive proof. 

Wherever the statements are not only inconsistent, but 
contradictory, the truth cannot by possibility lie between. 
If one says Caesar was a tyrant, and the other says he 
was not, one must be wholly right and the other equally 
wrong. It is also evident that there is never any rational 
and tenable mean between truth and falsehood. If the 
creed of the theist is true, that of the atheist must be 
quite false : and if the peculiar doctrines of the Trinita- 
rian are true, those of the Arian must be as erroneous as 
the Socinian's. 

2. Counting witnesses occurs where the testimony is 
estimated by the number of the witnesses, regardless of 
their character, the many being thought entitled to much, 
and the few, to little credit. A frequent instance is, the 
credit given to common rumor, where, as is usually the 
case, its origin, and consequently its value, are unknown. 
The prevalence of this practice is shown by the proverb, 
" what everybody says must be true" — the predicate 
meaning simply general report, which is often quite false. 
Testimonies should be weighed, not counted ; and conse- 
quently all those which have no weight, ought to go for 
nothing. One unexceptionable witness is entitled to im- 
plicit belief, while one million of worthless witnesses are 
entitled to none. But as counting is, in this case, a much 
easier process than weighing, it is often adopted. 

3. The paralogism of credulity occurs where we receive 
as satisfactory, testimony which is palpably unreliable, 
and which we could very readily perceive to be such, by 
a moment's consideration. This fallacy is very preva- 



282 Paralogisms. [Chap. XVII. 

lent, because it is fostered by several strong prejudices. 
The " Mississippi System" of Law, in France, and the 
" South Sea Scheme" of Blount, in England, which caused 
such wide-spread ruin, in the early part of the eighteenth 
century, are two notable instances of this kind. Other 
instances occur in the ready belief given to the hypei*bol- 
ical exaggerations of partisans. 

4. Scepticism is, where testimony which might be easi- 
ly ascertained to be conclusive, is rejected as unsatisfac- 
tory. This fallacy is simply the converse of the preced- 
ing, and has a similar origin. Hence both are often 
adopted by the same person, in reference to the same sub- 
ject. The favorable testimony is believed, though worth- 
less, and the unfavorable is rejected, though conclusive. 
Instances occur in the frequent rejection, by many, of sci- 
entific truths, established by evidence of which they could 
easily ascertain the conclusiveness. 

5. We either wholly overlook, or pass by without any 
serious attention, accessible testimony which materially 
affects the point under consideration, and assume that 
we have properly considered all the testimony, forming 
the paralogism of overlooking testimony. This fallacy 
naturally flows from the disagreeableness of a long inves- 
tigation of evidence ; and hence it is of frequent occur- 
rence. We have a common instance in the errors into 
which many historians have been led, by failing to con- 
sult important testimonies within their reach. 

6. Indiscrimination is where we either receive the 
whole of a testimony as satisfactory, because some parts 
of it are so, or reject it all as incredible, for a similar rea- 
son. The most faithful witness sometimes makes slight 
mistakes himself, or is misled by others, in matters of lit- 
tle moment, while his testimony may be very correct, in 
the main. On the other hand, the least credible witness 
generally relates some portion of the truth, even where 
his statements are substantially false. Yet, as it is much 
easier to accept or reject in the mass than to sift out 
truth from error, this fallacy is very prevalent. 

The paralogisms described in this section are frequent- 
ly combined with those of comprehension and other fal- 
lacies of testimony, a combination which often produces 
unhesitating conviction. 



Sec. 8.] Misinterpretation. 283 

§ 8. Paralogisms of Misinterpretation of Language. — Nature 
and Origin of this class of Paralogisms. — (1) Misunderstanding 
Archaisms. — (2) Misinterpreting Technicalities. — (3) Misinterpret- 
ing Ambiguities. — (4) Confounding different senses. — (5) Over- 
looking the Idiom. — (6) Following Etymologies. — (7) Mistaking 
the Style. — (8) Misplacing the Accent. — (9) Misconstruction. — 
(10) Mistaking Expressions. — Its Sources and Effects. — (11) Igno- 
rant Interpretation. — Its Origin. — (12) Misconception. — Frequent 
source of it. — (13) Fallacious Implication. — (14) Mistaking Allu- 
sions. — Where frequent. — (15) Fallacious Propriety. — Why fre- 
quent. — Effects of these Paralogisms. 

This class of fallacies comprises those cases in which 
we misunderstand or misinterpret statements which may- 
be perfectly fair and correct in themselves. They pro- 
ceed from the defects of language, ignorance, careless- 
ness, or prejudice. The following enumeration includes 
the most common : 

1. We affix to a term its ordinary signification at the 
present day, when, in reality, it is used in an antiquated 
sense, which we may term misunderstanding archaisms. 
It is apt to occur in interpreting ancient laws, or other 
compositions of a remote period, as where the word 
" publish" is taken to signify print and offer for sale, 
while it means to utter or proclaim in public, or where 
to " prevent" is interpreted to keep back, when it means 
to go before. 

~ 2. We overlook the nature of the composition,' and in- 
terpret words in their ordinary sense, when they are 
used technically, or conversely, which may be termed 
misinterpreting technicalities. By a gale a seaman un- 
derstands a high, strong wind, while, in ordinary lan- 
guage it means only a moderate breeze. 

3. Misinterpreting ambiguities is where we attach to 
an ambiguous expression a sense different from what was 
intended. This we are very apt to do where we know 
little of the subject or the language, and consequently 
misunderstand the context. Many instances occur in va- 
rious interpretations affixed by commentators to ambig- 
uous passages in ancient authors. 

4. Confounding different senses is where we blend va- 
rious significations of an expression, and unconsciously 
understand it now in one sense, and then in another, so 
that we form a confused conception of its import. The 
various confused significations attributed to such words 
as laio, idea, and nature, are instances of this fallacy. 



284 Paralogisms. [Chap. XVII. 

5. Overlooking the idiom occurs where we attribute 
to a foreign expression the exact import of the corre- 
sponding words in our vernacular, while there are im- 
portant differences in their significations. This is apt to 
occur where our knowledge of the idiom is imperfect, 
and we are not well acquainted with the history, institu- 
tions and manners of the people whose language Ave in- 
terpret. Virtus, in old Roman authors, does not gener- 
ally mean virtue, but valor / temperantia meant modera- 
tion in desires and pursuits, as well as in eating and 
drinking, while humilitas denoted abjectness or mean- 
ness, a very different thing from what we now under- 
stand by humility. 

6. Following etymologies is where we assume that a 
derivative or compound term has the exact signification 
of its original, when, in fact, they mean things widely 
different. This fallacy is of frequent occurrence in in- 
terpreting dead languages, where too much importance 
is often attached to etymology, owing to our other means 
of ascertaining its signification being very scanty. We 
often trow things that are not true / we may form p) % oJ- 
ects or speculations without being projectors or speculat- 
ors ; and. we are not bound to observe a holiday as a 
holy day. 

V. Mistaking the style occurs where that which is fig- 
urative is interpreted literally, or conversely. Such er- 
rors readily spring from overlooking the nature of the 
subject, or the differences between the style of one lan- 
guage and another. Some languages employ figures 
more freely than others ; and hardly any two use them 
precisely alike, in all cases. A common instance of this 
fallacy is, where figurative idiomatic phrases are taken 
in their literal acceptation. Such expressions as " a man 
beside himself," or "out of his mind," puzzle persons ig- 
norant of the English idiom, while the corresponding ex- 
pressions in their languages may be equally obscure to 
all those who are not familiar with them. 

8. Misplacing the accent is, where we attach a wrong 
meaning to an expression from mistaking the accented 
word. "The proposition " he who sins shall die," points 
out either the subject or the nature of the retribution, 
according as we accent the subject or the predicate. So 
if only the last word of the ninth commandment be ac- 
cented, it is made to forbid belying only our neighbours. 



Sec. 8.] MlSINTEEPKETATION. 285 

9. Misconstruction is where some word is assumed to 
qualify the wrong term, the true construction being mis- 
understood. This fallacy abounds in translations. The 
expression Aio te Romanos vincere posse, may be ren- 
dered " I say that thou canst conquer the Romans," — 
or " I say that the Romans can conquer thee." So redi- 
bis nimqnam peribis, signifies " thou shalt return ; thou 
shalt never perish" — or " thou shalt never return ; thou 
shalt perish" — according as we assume the pause before 
or after nunquam. 

10. Mistaking expressions occurs where we mistake 
the language employed, and assume that something has 
been uttered essentially different from the reality. We 
are very liable to adopt this fallacy, where the expres- 
sion is strange to us, and yet resembles one with which 
we are familiar. Many popular and typographical er- 
rors originate in this way, as — sparrow grass for aspara- 
gus, animals for mammals, Candia for Cardia, and Per- 
sians for JPierians. Sometimes the negative particle is 
overlooked ; and thus a meaning is assumed the direct 
contrary of what was intended. This paralogism has 
caused various slanders and bitter quarrels. 

11. Owing to mere ignorance of the language, we at- 
tach to an expression a meaning which it does not bear, 
forming the fallacy of ignorant interpretation. It arises 
chiefly from mistaking a term for another which it re- 
sembles, or adopting the first definition given in a dic- 
tionary. Many errors found in translations have origin- 
ated in this way. In various translations of Exodus, 
Chapter xxxiv., verse 7, one part is rendered so as to 
contradict, not only the whole tenor of Scripture, but the 
immediate context. 

12. Misconception is, where we comprehend only a 
part of the meaning of an expression, and unconsciously 
miss what is possibly the most important part. This 
fallacy frequently prevents truth from producing its le- 
gitimate effects on the mind, because that which is most 
effectual continues unknown, while the individual believes 
he understands the whole subject. The meaning attach- 
ed to many terms, — such as patriotism, benevolence, hu- 
mility, justice, modesty, and bravery — depends greatly on 
the character of the party addressed, so that four per- 
sons may receive as many different impressions from the 
same term. In order to comprehend the force and sig- 



286 Paralogisms. [Chap. XVII. 

nificance of another's language, we must frequently, not 
only attend to his circumstances, but also enter into his 
feelings. It is for this reason that persons of different 
characters and principles so often misunderstand, and 
consequently misrepresent, each other. 

A frequent instance of this fallacy is, where, in reading 
History or Biography, we attribute to the language the 
same signification which it would bear, if used by a con- 
temporary countryman of our own, when its real signifi- 
cation is widely different. 

13. Fallacious implication is, where we assume that 
the words imply something which, in reality, they do 
not. This is apt to occur where we are not well ac- 
quainted with the subject or the character of the author. 
A pernicious instance of it is, where the erroneous lan- 
guage of men, recorded in Holy Writ, is attributed to 
God, and thus fallaciously inferred to be true. . 

14. Mistaking allusions is, where we assume that the 
speaker or writer alludes to one thing when, in reality, 
he alludes to another. This fallacy is of frequent occur- 
rence in interpreting ancient and foreign languages, as 
we are apt to overlook the differences between ancient 
times or foreign countries and our own. Commentaries 
on ancient authors furnish many instances of this paralo- 
gism. 

15. Fallacious propriety is, where we force on the lan- 
guage an erroneous meaning, because we think it must 
have been the one intended, as, otherwise, the sense con- 
veyed would, in our opinion, be false or improper. The 
sense intended to be conveyed may be untrue or improp- 
er, or we may think so when it is otherwise, because our 
views of the subject maybe erroneous or defective. In- 
stances of this fallacy occur in the false glosses and mis- 
interpretations of Scripture arising from the erroneous 
assumption that any other interpretation would give a 
false or improper sense. 

As we are generally unwilling to believe that our own 
views are wrong, and always desirous of finding them 
tally with those of men whom we respect, this fallacy is 
of frequent occurrence. 

Fallacies of misinterpretation are apt to be very per- 
nicious in their effects, because they frequently refer to 
subjects of great importance, while their existence is un- 
suspected by their victims. Not only is language an im- 



Sec. 1.] Sophisms of Confusion. 287 

perfect weapon wielded by an arm which is ever liable 
to miss its aim, but its heaviest and most direct blows 
are often parried by carelessness, ignorance, prejudice, or 
stolidity. 



CHAPTER XVIII. 

OF SOPHISMS, OK FALLACIES OF INTERMEDIATE EEASON- 
ING. 

§ 1. Sophisms of Confusion. — Nature of this class of Fallacies. — 
(1) Sophistical Connection. — Kelations of Conclusions and Pre- 
mises. — Influence of Prejudices. — (2) Inferring the Converse. — 
Why it often escapes detection. — Eelations of a Proposition to its 
Converse. — (3) Altering Propositions.— How sometimes disguised. 

This class of fallacies comprises those cases in which 
we draw inferences not implied in our premises, owing 
to our mistaking one proposition for another which re- 
sembles it, but is yet essential different. The following 
are the principal kinds : 

1. Sophistical connection is, where premises are as- 
sumed to be true or false, according to our opinion of 
the conclusion deduced from them; or, conversely, the 
conclusion is assumed to be true or false, according as it 
is implied in the premises or not. 

False premises are often employed to prove true con- 
clusions, and unobjectionable premises are often employ- 
ed to prove false conclusions, while false conclusions may 
be implied in false premises. The premises and the con- 
clusion, again, may be both true, while the latter is not 
implied in the former : but the only legitimate inference 
is, that the conclusion is not proved by those premises ; 
for it may be conclusively proved by other unobjection- 
able premises. 

Where the conclusion is implied in the premises, the 
former stands as high as the latter, but no higher. If 
these be cognitions, so is the conclusion ; and the same 
relation holds between them when the premises are only 
probabilities : that of the conclusion is as strong as the 
latter's, but not stronger. It must be carefully observed, 
however, that the converse does not hold true. False or 
doubtful premises do not prove false or doubtful conclu- 
sions, nor exclude other proofs that they are true. To 



288 Sophisms. [Chap. XVIII. 

warrant us in assuming that a conclusion is false, we 
must have positive proof that it is so ; and the fact that 
the premises may be false, or that the conclusion may 
not he implied in them, furnishes no such proof. 

This fallacy is one into which we are very readily led 
by prejudices. We are apt to pay too little attention to 
our premises, when they establish a favorite conclusion ; 
and when the conclusion is strongly repugnant to our 
desires, we are inclined to reject the premises which 
prove it, without giving them a careful consideration. 

2. Inferring the converse occurs where we infer that a 
proposition is true, because its converse is true, as when 
we infer that every equiangular triangle is equilateral, 
because every equilateral triangle is equiangular. This 
fallacy often produces conviction, not only on account of 
the great resemblance which a proposition bears to its 
converse, but from the fact that the converse is often 
true, although the case is generally otherwise. Although 
every horse is a quadruped, yet every quadruped is not 
a horse. We may, indeed, express a proposition in such 
a way as to render its converse true, by making its sub- 
ject and predicate identical : but propositions of this 
class are only an exception to the general rule ; and the 
cases in which the converse is true accidentally (as in the 
instance mentioned above) are too few to be taken into 
account. 

A common example of this sophism is, where we infer 
that one thing is identical with another, because both be- 
long to the same general class. White is a color, and 
black is a color : therefore black is white. So, every wise 
man carefully considers the future, and John does so : 
therefore he is wise. It is assumed, in all such case?, 
that the converse is true ; and hence the fallacy. Al- 
though white is a color, every color is not white. 

3. Altering 2>ropositions is where we erroneously as- 
sume, in the course of an argument, that something has 
been already proved, or has appeared to be true, which 
is employed accordingly, as a sound premise, while it 
diflers materially from that whose place it thus usurps. 
The previous proposition generally bears some resem- 
blance to the other : but it is less extensive, or it has 
been proved only with certain qualifications or restric- 
tions, which are afterwards overlooked, or it is proved 
true only in another sense from that assumed, or it lacks 
something important which is afterwards added, 



Sec. 2.] Altering Propositions. 289 

This fallacy is greatly fostered by the defects of lan- 
guage ; and it is often disguised by being combined with 
ambiguous expression. Here the ambiguous terms are 
used in different senses, throughout the argument, while 
some of these are not true, in the sense in which they 
would require to be so, to render the reasoning valid. 
When it is said that " three and two are five, and five is 
one number: therefore three and two are one number" 
— the word are, in the first proposition, should have the 
sense of" are identical with," in order to sustain the con- 
clusion, as understood ; and, in this sense, the proposition 
is false. Three and two are no more five than so many 
copper coins are one silver coin. They are only equiva- 
lent to five ; and, in this sense, the conclusion is proved : 
three and two are equivalent to one number. So it can 
be proved that " some men are wise," and " some men 
are fools :" but it does not thence follow that fools are 
wise, since the expression " some men" denotes totally 
distinct objects, in the two propositions. 

An amusing instance of this combination is found in 
the old story of Protagoras the Sophist, and his pupil 
Euathlus. The former taught the latter Rhetoric, on 
condition that he should be paid for his services, if his 
pupil were successful in pleading his first case. Euathlus 
having failed to commence practice, Protagoras sued 
him ; and he pleaded his own case. So this was his first 
case. Therefore Protagoras was bound to win : for, if 
the decision were in his favor, Euathlus was bound to 
pay, in virtue of the judgement ; and if it was otherwise, 
Euathlus gained his case, and, therefore, was bound to 
pay, in virtue of the contract. But, on the other hand, 
Euathlus was bound to Avin : for, if the decision was, that 
he should pay, he had lost his first case, and, therefore, 
should pay nothing, by the terms of the contract : but if 
the decision was otherwise, this left him free. 

§ 2. Sophisms of Generalization. — Nature of these Fallacies. — 
(1) Sophistical Extension. — Frequent source of it. — With what oft- 
en combined. — Influence of the Combination. — (2) Sophistical In- 
clusion. — (3) Sophistical Contraction. — (4) Sophistical Exclusion. 
— (5) Sophistical Combination. — Why often undetected. — (6) Im- 
aginary Universality. — Why prevalent. — Caution. 

This class consists in generalizing further than our ac- 
tual knowledge warrants, or the converse : and there are 
six principal kinds of it. 

N 



290 Sophisms. [Chap. XVIII. 

1. JSophisticcd extension is where we assume that things 
found together in certain cases, are always connected, or 
that a certain property is common to every one of a 
class, since it belongs to several of its individuals or 
tribes. In other words, we mistake an empirical for a 
scientific generalization. Some men have been deceived 
by several of their neighbours ; so they infer that all 
mankind are dishonest : many have been found, under 
certain circumstances, to lie ; therefore it is inferred that 
nobody can be safely believed, under any circumstances. 
Others find that certain things related by historians are 
untrue : so they conclude that all history is unworthy of 
credit. Many things are uncertain, and many falsehoods 
have been believed as truths : therefore they infer that 
nothing is certain. 

Many fallacies of this kind originate in the fact that a 
certain property has, not unfrequently, been found to 
extend beyond the cases first observed ; and hence it is 
erroneously inferred that it extends indefinitely. A negro 
of Central Africa is apt to infer that all men are black 
or brown, while some natives of Northern Europe once 
inferred that all mankind are white. The experience of 
so many cases leads to a tacit inference that they are the 
effects of some constant and unvarying cause, which, how- 
ever, may have no existence. 

This fallacy is frequently combined with those of com- 
prehension. Not only is there no real induction, but the 
facts on which we reason are either inaccurately or par- 
tially observed ; and a more extended or careful view 
would speedily explode the generalization. Judicial 
Astrology is a notable instance of this combination. It 
assumed that the position of the planets, at the time of 
a person's birth, determined his character and future 
destiny, although many men, born at the same time, 
have, in every age, exhibited the most different charac- 
ters and fortunes, on which the aspect of the planets had 
not, in reality, the least influence. 

2. In sojrfiistical inclusion we assume, without satis- 
factory proof, that several things which agree in some 
respects, agree in others also, and thus infer that all be- 
long to a particular class, when, in fact, they may not. 
Thus, naturalists have sometimes ranked a species with 
a genus to which it did not belong, on their own princi- 
ples. So men often attribute to others characters which 



Sec. 2.] Fallacious Generalization. 291 

they do not possess, because they exhibit certain appear- 
ances which accompanied the supposed character in other 
cases, but does not, in the case in question. In the same 
way, the opinions of certain persons have been classed 
with a school to which they do not belong, because they 
have several things in common; and all diseases have 
sometimes been classed under a few general heads, so 
that affections essentially different, and requiring differ- 
ent treatment, were classed together. Other common 
instances of this sophism are, that things essentially dif- 
ferent are quite alike, because they happen to be called 
by the same name, and that language faithfully expresses 
the realities of nature, in every instance, when, in fact, it 
fails to do so, in many important cases. 

3. Sophistical contraction occurs where an induction 
is mistaken for an empiricism, and it is assumed that the 
facts beyond those immediately observed are different, 
when, in reality, they are as uniform as the course of na- 
ture. This fallacy is the converse of sophistical exten- 
sion : and we have an instance of it in the common remark 
that a certain kind of diet is very conducive to the health 
of the speaker, although he admits that it has been found 
injurious in other cases ; and, in fact, there is conclusive 
proof that it must always be so. Another* common in- 
stance is, where a man infers that he can, by some means 
or other, escape the certain and inevitable consequences 
of a dissipated life, while he is well aware that they have 
followed in other cases. 

4. In sophistical exclusion we assume, without satis- 
factory proof, that things which differ in some respects, 
differ in others also, and consequently infer that they be- 
long to different classes, when possibly they do not. It 
is the converse of sophistical inclusion, and leads us to 
exclude an individual or a species from its proper class. 
Thus it is often assumed that a man does not possess a 
certain character, because he does not exhibit peculiari- 
ties which accompanied such a character in other cases, 
but in fact do not, in his case. Another instance is, 
where it is inferred that things are materially different 
because they are called by different names, while they 
may all be modifications of the same thing, and essen- 
tially alike. Naturalists fall into this sophism when they 
form a mere variety into a distinct species, or exclude a 
species from its proper genus, because it does not ex- 



202 Sophisms. [Chap. XVIII. 

hibit peculiarities which ave erroneously believed to char- 
acterize the class frorn which it is excluded. 

5. In passing from several special propositions to a 
general one, which professedly embraces them all, and no 
more, something material is added or excluded, forming 
the fallacy of sophistical combination. It frequently es- 
capes detection, especially in elaborate arguments, be- 
cause several of the particular propositions are unexcep- 
tionable, and the attention is diverted from the objection- 
able part, which may form only a small, though possibly 
an essential, portion of the general proposition. Foren- 
sic arguments frequently exemplify this fallacy, by draw- 
ing, from the testimonies given, some general conclusion, 
which involves a material assumption of which no satis- 
factory proof has been given. 

6. Imaginary tiniversality is where we assume that a 
proposition is true or false universally, because it has 
been proved to be so generally. This sophism is of fre- 
quent occurrence, because there is a general prejudice yi 
favor of excluding all exceptions to general laws or rules, 
while these may exist notwithstanding. Most men are 
rational and two-handed, but some are not. We can 
never safely admit the universality of a proposition ex- 
cept where this has been rigidly proved ; and this can 
never be done, beyond the bounds of necessary truth. 

§ 3. Sophisms of Causation. — (1) False Cause. — Important Distinc- 
tion. — (2) False Effect. — Error regarding Experience. — (3) Con- 
founding Cause and Effect. — (4) Hypothetical Causes. — (5) Mis- 
taking the chief Cause. — (6) Mistaking the chief Effect. — (7) Mis- 
taking the ultimate Catise.— (8) Sophistical Explanation. — (9) So- 
phistical Induction. — (10) Sophistical Proof. — Relation of Proof to 
Cause. — (11) Sophistical Relation. — Why prevalent. — (12) Ex- 
cluding Causes. — (13) Excluding Effects. — Why prevalent. — (14) 
Imaginary Effect. — Caution. — (15) Imaginary Cause. — Frequent 
Combinations. — By what this class of Sophisms is particularly af- 
fected. 

This class comprises those sophisms in which we err 
regarding causes and effects. The following enumera- 
tion includes the most common. 

1. False cause occurs where a mere antecedent or con- 
comitant is inferred to be a cause, while the effect may 
depend wholly on other agencies. A uniform antecedent 
or concomitant is a sign of the consequent: but, before 
we are justified in considering it a cause, we must know 
that it is concerned in producing the effect. 



Sec. 3.] Sophisms of Causation. 293 

Many superstitions are examples of this fallacy. A 
pagan fails to present the usual offerings to the gods : he 
is taken sick, and at once attributes this to the supposed 
anger of the offended deities. Another has used some 
silly charm, before engaging in an important undertak- 
ing : he succeeds, and attributes it to the influence of the 
charm. Medicine and politics, also, furnish numerous in- 
stances of this fallacy. A person takes a medicine, and 
recovers from his disease : the cure is attributed to the 
remedy, although possibly it may have only retarded his 
recovery, which was effected by the healing powers of 
the system, in spite of the pernicious effect of the medi- 
cine. So politicians have sometimes attributed public 
prosperity or adversity to certain laws, which, in fact, 
operated wholly the other way. 

2. False effect is, where a consequent or concomitant is 
inferred to be the effect of an agency of which it may 
possibly be quite independent. A man's success, in one 
case, and his failure, in another, have been frequently 
deemed the effects of agencies by which they were not, 
in the least, influenced. The Moon is incessantly chang- 
ing, and so is the weather : hence changes of the former 
are speedily followed by changes of the latter, as a mat- 
ter of course ; and yet these have often been believed to 
be effects of the former, although further observation 
would show that the two classes of phenomena have not 
the least connection with each other. 

Where a certain change follows the supposed cause, it 
is sometimes confidently declared that experience proves 
the point, when all it proves is, that one followed the oth- 
er, and it may have been its effect no more than night is 
the effect of day, or winter the effect of summer. The 
premonitory symptoms of a disease are its uniform ante- 
cedents : but, instead of being its cause, they are only 
early effects of the common cause. 

3. We mistake the order of cause and effect, making 
that the cause which is, in reality, the effect, and con- 
versely, forming the sophism of confounding cause and 
effect. We are very liable to fall into this error where 
the cause and effect appear simultaneously, or where the 
effect reacts and strengthens the cause, or where two 
things mutually produce each other, so that what is, in 
one case, the effect, is, in another, the cause. Thus loose 
thinking produces loose acting, while the latter increases 



294 - ?msits. [Chap. XVEH. 

and confirms the former, or even produces it independ- 
ently. A pernicious instance of this fallacy is, the opin- 
ion that severe training renders children hard; 
many who bore it are so. They are not hardy, b e 
they were treated severely ; but they bore such treat- 
ment unflinchingly, because they were originally 
hardy ; and they would be hardier than tfa if they 

had been more rationally treated. The sophism has 
caused the deaths of many thousands of children, and 
loss of health and strength to still greater numb-: 

4. JBj thet •■ occurs where supposed agencies 
are inferred to be the causes of the effect in question, 
when possibly they have no existence. This fallacy is 
frequently exemplified in the motives assigned for the 
actions of others, where these are not, in reality, known. 
A man of good principles i ; apt to assign niotr 
which the party in question may be an entire stranger, 
while persons of a different character are inclined to at- 
tribute everything to bad and sordid motives, such as 
usually sway themselves. This fallacy abounds in Scho- 
Iastic Physics. Water rose in a pump, because nature 
abhorred a vacuum : descending bodies moved faster and 
faster, because their motion was violent, and not natural : 
air occupied the upper regions, because that was its prop- 
er place : muscular contraction was effected by the ani- 
mal spirits — and so forth. 

5. M ~ ' ~ se occurs where one of 
eral agencies is inferred to be the sole or chief, when it 
is possibly only a minor cause, having comparatively lit- 
tle influence on the effect. A man whose constitution 

;-en ruined by dissipation, takes a slight cold, and 
His death is attributed to the cold, although it 
1 have produced no serious effect on him, if his con- 
stitution had retained its original vigor. Another com- 
plains of bad health, which he attributes chiefly to hard 
study, labor, or exposure, when, in fact, it has proceeded 
mainly from luxurious living. 

:-. inferring that a minor 
ondary is the chief effect. A broken down de- 
bauchee will sometimes complain of a comparatively 
trifling evil result of his virion- 3, and overlook 

the fact that he is a total wreck : so a politician some- 
times inveighs against a law as very bad. because it pro- 
- some evil, while he overlooks the fact that it pro- 
duces a much greater amount of s^ood. 



Sec. 3.] Sophisms of Causation. 295 

7. Mistaking the ultimate cause is, where we infer that 
some intermediate is the ultimate cause, and requires no 
further explanation, when, in fact, the last at which we 
have arrived must be attributed to some remoter cause. 
Instances of this fallacy aboimd in various treatises on 
Physics. When a phenomenon has been traced to elec- 
tricity, for example, it is inferred that the ultimate cause 
has been disclosed, whereas the motions of electricity re- 
sult from one or more agents beyond itself, as certainly 
as it is the immediate cause of the phenomenon in ques- 
tion ; and, until that has been unfolded, we continue ig- 
norant of the ultimate cause. 

8. Sophistical explanation occurs where it is inferred 
that the cause has been clearly proved when only some 
explanation is given, which possibly refers the phenome- 
non to some acknowledged law, but which assigns no 
real cause. " India rubber contracts, when it has been 
stretched, because it is elastic : the particles of solids 
stick together, because they are adhesive : and streams 
flow downward, because all bodies gravitate towards the 
center." Such expressions only refer a particular phe- 
nomenon to a general law, and unfold the cause of noth- 
ing. They only state that the phenomenon is owing to 
what produces something else, on which no light is 
thrown. 

9. Sophistical induction is, where inductive truths are 
mistaken for efficient causes. This sophism differs from 
the preceding in attributing causal power to a mere law, 
whereas the other refers us' to some real, though unde- 
fined, cause, which produces the general phenomenon. 
Instances of it are found in statements which attribute 
to the laws of electricity, magnetism, and gravitation, the 
numerous changes exhibited by their several phenomena, 
and which result from some force that is unexplained, or 
even unsuspected. A law is merely a command, or a 
general truth, and cannot be an efficient cause of any- 
thing. Laws and agents are totally different things ; and 
this fallacy consists in confounding them, and attributing 
to the former what cannot possibly belong to anything 
but the latter. 

10. Sophistical proof occurs where we mistake the 
proof for the cause, and attribute to the former what be- 
longs to the latter. When we have proved that a cer- 
tain agent operates, which uniformly produces a particu- 



296 Sophisms. [Chap. XVIII. 

lar effect, we have implicitly proved the existence of the 
latter. But the converse does not hold true : we may 
prove that a certain effect exists without proving any- 
thing regarding its particular cause. The appearance of 
ice on the waters is a proof that there has been cold 
weather : but, instead of being the cause, it is an effect. 
This fallacy is fostered by the habit of employing the 
same conjunctions to denote causes and proofs. 

1 1 . Sojildstical relation is, inferring that effects resem- 
ble their causes, or that effects of a common cause are all 
alike in kind, and proportional to its intensity; or, con- 
versely, that different effects must proceed from agencies 
different in kind, which are proportional to the effects. 
This sophism is very prevalent, because the inferences 
frequently hold true, and hence the exceptions are over- 
looked. Yet these are neither few nor unimportant. 
Thus, most of those agencies which excite pleasant sen- 
sations, produce pain when they act with intensity, such 
as heat, light, and various sounds. So the effects of 
property on a man's well-being are by no means propor- 
tional to its amount. The contrary inference is a very 
common and pernicious instance of this fallacy. An ap- 
peal to experience is generally necessary, in order to as- 
certain whether the relations inferred by this sophism 
really exist, and also to ascertain the common origin of 
the varying effects of the same cause, acting with differ- 
ent degrees of intensity. 

12. Excluding causes is where we attribute a phenom- 
enon solely to certain agencies, and exclude or overlook 
others, which operate in its production. The fact that 
an agency does not by itself produce a given effect, by 
no means proves that it is not instrumental ;n its produc- 
tion. Water alone will not decompose organic sub- 
stances ; yet it is an active agent in such decomposition. 
So the Sun has a very perceptible effect on the tides, and 
causes the difference between spring and neap tides, al- 
though the Moon's influence is much more conspicuous. 
A common instance of this sophism is, denying that the 
art of reading is not an important means of moral and 
intellectual discipline, because its effects may be nuga- 
tory, unless aided by other agencies. So it is sometimes 
inferred that certain bad habits have not operated in pi*o- 
ducing disease or premature death, because other agen- 
cies have operated, and some persons have been long- 
lived who were addicted to those habits. 



Sec. 3.] Sophisms of Causation. 297 

13. Excluding effects is, where "we exclude or ovei'look 
certain effects of an agency, and infer that some others 
are the sole effects. This frequently happens in investi- 
gating the results of laws and of morbific agencies. An 
instance of it occurs in the common opinion that the im- 
mediate effects of alcohol on the human frame are its sole 
effects, and that it is not instrumental in producing chron- 
ic disease or permanent insanity. 

14. Imaginary effect attributes to a certain cause an 
effect which does not, in reality, exist. Sometimes there 
are phenomena resembling that which is assumed to ex- 
ist ; but they are materially different. In other instances, 
the assumption is partially true, yet it differs essentially 
from the reality. A non-existing phenomenon can have 
no cause ; and consequently any argument ostensibly 
proving its cause, must be sophistical. Hence, before 
inquiring into the cause of a supposed or assumed phe- 
nomenon, we should ascertain whether it is a fact. Cases 
are not rare in which much time has been spent in inves- 
tigating the causes of imaginary effects, which never ex- 
isted. An instance of the sophism occurs when it is be- 
lieved that a man recovered, by means of a certain treat- 
ment, from a disease which he never had. So a politician 
sometimes attributes to certain laws or public acts, good 
or evil which never existed. 

15. Imaginary cause occurs where an effect is attrib- 
uted to an agency which never existed, and which evi- 
dently can produce no effect. Consequently any proof 
that it has done so must be fallacious. A physician 
sometimes attributes the cure of his patient to a medi- 
cine which was duly prescribed, but which the latter 
never took ; and a politician has been known to attrib- 
ute good or evil to acts of the ruling powers which were 
never performed. This and the preceding fallacy are al- 
ways combined with some paralogism, which they dis- 
guise and render less liable to detection. 

All the sophisms of causation are frequently combined 
with those of comprehension and signs. Facts are either 
overlooked, misapprehended or misinterpreted ; and then 
we reason sophistically upon a wrong view of the sub- 
ject. A certain phenomenon, for instance, is assumed to 
be a uniform antecedent, when careful and continued ob- 
servation would show that it is only an occasional antece- 
dent ; and then it is sophistically inferred to be the cause. 
N2 



298 Sophisms. [Chap. XVIII. 

This class of fallacies is particularly affected by igno- 
rance and prejudices, since the truth is not generally ob- 
truded on our Comprehension, but must be learned by 
a close and cautious view of the subject. 

§ 4. Sophisms of Probability. — Nature of these Fallacies. — (1) In- 
ferring the Probable. — (a) Inferring Hypotheses. — (b) Accumula- 
ting Probabilities. — Important Distinction. — (c) Friends' Opinions. 
— (d) One-sided Arguments. — (e) Harmonizing Conclusions. — 
Why frequent. — (f) Contingent Connective. — Frequent Combina- 
tion. — (g) Incomprehensible Connective. — Important Distinction. 
— (h) Inconclusive Investigation. — (i) Sophistical Leap. — Distinc- 
tion. — (2) Rejecting the Improbable. — (a) Discordant Opinion. — 
Its extensive Influence. — (b) Overlooking the Alternative. — Why 
prevalent. — Its Operation. — (c) Rejecting Theories. — Frequent 
source of this Sophism. — (d) Severing Probabilities. — (e) Enemies' 
Opinions. — (f) Mortifying proofs. — Effects of this Sophism. — (g) 
Imaginary Absurdity. — Cause of its great Influence. — (h) Sophist- 
ical Distinction. — Where frequent. — Means of determining wheth- 
er a Distinction is material. — (3) Varying Probability. — (a) Exag- 
gerating Probability. — Frequent Combination. — (b) Diminishing 
Probability. — (c) Exaggerating Improbability. — (d) Diminishing 
Improbability. — Combinations. — Why such Fallacies prevalent. — 
Two Sources of them. — Why Fallacies of Probability are very prev- 
alent and influential. — Frequent Combinations. 

This class of sophisms consists in confounding proba- 
bility with certainty, or mistaking the character of the 
probability : and there are three principal kinds of it, 
each of which comprises several sorts. 

1. We infer that a proposition is true, because it ap- 
pears probable, while it may, in reality, be false. This 
we term inferring the probable, of which the following 
sorts are common. 

(a.) Inferring hypotheses is where we infer that an 
hypothesis or supposition is true, because it is rendered 
probable by various facts, when it may possibly be dis- 
provable by conclusive arguments or evidence. The his- 
tory of science exhibits many instances of this fallacy, 
from the crystaline spheres, epicycles and eccentrics of 
the ancient astronomers, to the habitable Moon and plan- 
ets of later ages. An hypothesis often appears so beau- 
tiful, harmonious, complete, and systematic, that its au- 
thor or his disciples are ready to adopt it as established, 
without requiring proof that it is true, although it may 
possibly be easy to discover facts by which it is com- 
pletely exploded. 

A frequent instance of tins modification is, inferring 



Sec. 4.] Sophisms of Probability. 299 

that a certain operative agency, which uniformly pro- 
duces the effect in question when it is not counteracted, 
must have actually produced it, while possibly the ordi- 
nary result was prevented by some counteracting agen- 
cy. Or, conversely, it is inferred that a known effect 
must have proceeded from a particular agency, when it 
may possibly have resulted from any of several others. 
By this means persons have been charged with crimes 
that were never committed, and the misdeeds of one 
have been attributed to another, against whom there 
were suspicious circumstances. 

(b.) Accumulating probabilities occurs where it is in- 
ferred that a proposition is true, because it is supported 
by several dependent probabilities, or probabilities of 
probabilities. These are confounded with concurrent 
and independent probabilities, where every one strength- 
ens the preceding, instead of weakening it, as happens 
with the former class. The implicit credit frequently 
given to the statements of persons who derived their in- 
formation from each other, is a common instance of this 
fallacy. It is not perceived that, in such cases, the more 
witnesses, the less credibility. 

(c.) Friends' opinions is, where we infer that a propo- 
sition is true, because our friends, or persons whom we 
deem competent witnesses and good judges, state or be- 
lieve it, when there is no conclusive proof. Many men 
hardly ever investigate a subject of any difficulty inde- 
pendently : they inquire what such and such men say or 
think of it, without ever seeking or finding any conclu- 
sive proof; and then they adopt those men's opinions as 
known truths. A common case of this form is, where 
we receive as conclusive the testimony of a witness of 
whom we think favorably, while it establishes only a 
probability. 

(d.) The sophism of one-sided arguments is, where ar- 
guments have been adduced which render the proposi- 
tion in question probable, and, therefore, it is inferred to 
be true, while other arguments, which militate against 
it, are overlooked. One of the most common cases is, 
the erroneous opinions which many hold regarding their 
own characters, desires, pursuits or expectations. The 
arguments which favor the bright side are seized with 
avidity, and adopted as conclusive, while those of a con- 
trary tendency are overlooked, although they may possi- 



300 Sophisms. [Chap. XVIII. 

bly be more cogent than the others. Hence the errone- 
ous views which men have so frequently held regarding 
the character of themselves, their nation, age, religious 
denomination or political party; and hence pride and 
self-sufficiency, coupled Avith contempt for others, and a 
fixed determination to persist in present belief and 
courses, right or wrong. 

(e.) Harmonizing conclusions is, "where we infer that 
a proposition is true, because it appears to harmonize 
with some real or supposed truth, or it agrees with our 
own opinions, or its reception as true removes a diffi- 
culty. This form has been a fertile source of error, be- 
cause one truth always harmonizes with another, and we 
are strongly inclined to adopt as true what tallies with 
our own views and opinions. Instances of it occur in 
the numerous cases in which the false statements of his- 
torians, travelers or newsmen have been received as true, 
because they accorded with the opinions of those to 
whom they were addressed. Another common instance 
is, where we receive a charge against a person as true or 
false, according to our opinion regarding his previous 
character, while the evidence may prove the reverse. 

(f.) Contingent connective is, where a contingent truth 
is employed as the connective of a syllogism, instead of 
an intuition. A common instance of this form is, where 
an induction is employed as a connective, as when it is 
argued that a certain person must die, since all men are 
mortal, or that an animal must have such an organiza- 
tion, since every one of the species has it. The fallacy 
is often combined with that of false extension, the as- 
sumed induction being only an empiricism, as when it is 
inferred that a certain man must be of such a character, 
since every one of his nation bears it, when, in fact, it is 
only a prevalent character among them, and by no means 
universal. 

(g.) Incomprehensible connective occurs where a prop- 
osition is employed as a connective, because its contra- 
dictory is incomprehensible, whence it is erroneously as- 
sumed to be self-evident, when it may possibly be false. 
Instances of it occur in some mathematical demonstra- 
tions and philosophical speculations. Thus, it has some- 
times been assumed as self-evident that a vanishing quan- 
tity must have some finite value, and that duration can- 
not be eternal, nor extension infinite. A notable instance 



Sec. 4.] Sophisms of Probability. 301 

is, the ancient puzzle which professed to prove that the 
swift-footed Achilles could never overtake a turtle, be- 
cause the latter always advanced a little, while the man 
was traversing the intervening space. This was assumed 
to be subdivided indefinitely; and, as we cannot com- 
prehend an infinite number, we are apt to infer that it 
would take an endless time to traverse an infinite num- 
ber of small spaces, whereas the time of traversing the 
intervals would become shorter, exactly as they became 
smaller, and one minute can be divided and subdivided 
without limit, as well as one mile. 

There are many truths that transcend our comprehen- 
sion : and, consequently, we can never safely assume that 
a proposition is necessarily true, because we cannot com- 
prehend its contradictory. This raises only" a probabil- 
ity that it is true ; but, instead of being necessarily so, 
there is sometimes conclusive proof that it is false. The 
incomprehensible and the self-evidently impossible, al- 
though often confounded, are widely different things. 

(h.) Inconclusive investigation is, where we have in- 
vestigated the character of a proposition, and we infer 
that it is certainly true, while our labors establish no 
more than a probability, because the criterion of truth 
has not been properly applied, on one or more points. 
Instances of this form abound in historical, scientific, and 
judicial investigations, as well as in common life. 

(i.) The sophistical leap occurs where the proposition 
has appeared to be very probable, and, therefore, it is in- 
ferred to be certain, the wide gulf that separates proba- 
bilities from certainties being overleaped. Future evi- 
dence or discoveries may disprove the strongest proba- 
bility, and show that it is wholly false, or at least annul- 
led by an equally strong counter probability, whereas 
they cannot, in the least, invalidate a certainty, although 
they may corroborate it. When once established, a cer- 
tainty continues unchangeable ever afterwards, while 
probabilities are subject to change from, year to year, or 
even from hour to hour. 

2. Rejecting the improbable is, where we infer that a 
proposition is false, because it appears to be improbable, 
when it may possibly have been proved conclusively. 
The following are the most common sorts. 

(a.) Discordant opinion is, where we infer that a prop- 
osition is false or unproved, because it conflicts with our 



302 Sophisms. [Chap. XVIII. 

own opinions or experience. Thus one error often leads 
to several others, and the rejection of many truths. The 
fact that there are antipodes was long rejected by the 
great mass of mankind as an absurdity ; and, until re- 
cently, accounts of showers of stones having fallen from 
the sky, were generally classed with the old story of 
Vulcan having fallen from heaven upon Lemnos. This 
fallacy has been very prevalent, owing to the general 
tendency of men to make their individual views and ex- 
perience the standard of truth, and to reject whatever is 
incompatible with them, although the former may be er- 
roneous, and the latter very narrow. 

(b.) Overlooking the alternative is, where we infer that 
a proposition must be false, because there are proofs that 
it is highly improbable, while, in reality, its rejection in- 
volves a much greater improbability, or even an impossi- 
bility. This form is of frequent occurrence, because a 
very high degree of improbability is readily confounded 
with an impossibility. The infinity of extension and the 
eternity of duration, appear highly improbable, as they 
are undoubtedly incomprehensible : yet, if we deny those 
attributes, we must admit that the former has bounda- 
ries, and that the latter had a beginning, two things 
which are absolutely impossible. 

Owing to this fallacy, men often adhere to an opinion 
which involves much greater difficulties than that which 
they reject for its improbability. They dwell upon the 
difficulties of the latter, and overlook the fact that these 
are not conclusive, and that greater difficulties are in- 
volved in the alternative, which they must receive, if the 
other is rejected. Thus, many historical statements have 
been rejected as improbable, where the falsity of the tes- 
timony would be a much greater improbability, or even 
an absurdity. 

(c.) Rejecting theories is, where an hypothesis which 
has been proved to be true, is rejected, because it ap- 
pears improbable. This is frequently owing to its clash- 
ing with some favorite, but groundless, hypothesis of the 
rejecter: but it often proceeds from his being too igno- 
rant, indolent, or narrow-minded to appreciate the proofs 
by which the hypothesis is established. 

(d.) Severing probabilities consists in rejecting conclu- 
sive circumstantial evidence, because the separate cir- 
cumstances establish only a probability, which is believed 



Sec. 4.] Sophisms of Probability. 303 

to be rebutted by a greater antecedent probability against 
the conclusion, while the combined force of all the evi- 
dences is overlooked. The fallacy is like maintaining 
that twenty men cannot raise a Aveight, because none of 
them separately can do it. A common instance is, where 
a man charged with a crime, is believed to be innocent, 
on account of his previous good character, and the evi- 
dence against him being wholly circumstantial, although, 
taken altogether, it may be quite irrefragable. In the 
same way, another is believed to be guilty, because of 
his bad reputation, and none of the exculpatory circum- 
stances being conclusive ; although all of them taken to- 
gether may be quite so. 

(e.) Enemies' opinions consists in inferring that a prop- 
osition is false, because it is rejected by those of whom 
we think highly and adopted or testified by others to 
whom we are opposed or unfriendly, while the proof by 
which it is sustained has never been properly, if at all, 
examined, and, for anything that appears to the contrary, 
it may be quite conclusive. This sophism is the con- 
verse of friends' opinions, and operates similarly. A 
common instance is, where we reject as unsatisfactory 
the conclusive testimony of a witness whom we dislike, 
for which reason we think it highly improbable, and 
therefore not credible. 

(f) Mortifying proofs is, where an established prop- 
osition is rejected, because it is highly distasteful to our 
wishes or feelings, whence we infer that it must be false. 
Prejudice makes it appear very improbable, and, there- 
fore, it is inferred that there must be some radical defect 
in the argument or testimony by which it is sustained. 
Thus, when it has been proved that a man's conduct, on 
a particular occasion, has been highly culpable, he imme- 
diately appeals to the supposed purity or excellence of 
his motives, as invalidating the argument, which is not 
in the least affected by their character. So men are apt 
to believe that arguments or testimonies which militate 
against the excellence of their own character, conduct, 
or position must be fallacious, although they may be 
quite the reverse. 

This sophism fosters selfishness and bad passions, and 
throws strong obstacles in the way of reforming evil 
practices, or correcting erroneous opinions. It is the 
counterpart of the fallacy of one-sided arguments, which 
it generally accompanies and strengthens. 



304 Sophisms. [Chap. XVIII. 

(g.) Imaginary absurdity is, where a proposition is 
inferred to be false, because it is erroneously believed to 
contradict self-evident or palpable truth. Conclusive 
proof has often been thus rejected. It is so pleasant and 
easy to adopt current opinions as true, so difficult, in 
many cases, to find truth, and so unpleasant to discover 
we have believed error, that a great portion of mankind 
have been misled by this fallacy, on some occasion or 
another. The faithful statements of travelers and histo- 
rians have been rejected as false, on no better grounds 
than that they were at variance with the views of those 
who heard or read them, regarding the criterions of 
truth. 

(h.) Sophistical distinction is, where we infer that the 
proposition in question is unproved, because it appears 
to differ, in some respects, from that which has been 
proved, while the difference is, in reality, quite immate- 
rial. When the question has been proved in effect, dif- 
ferences in the mode of expression, or some immaterial 
particular, are evidently of no consequence. This fallacy 
is sometimes adopted by controversialists, when other 
arguments have failed. 

In determining whether a distinction is material, we 
must look to the nature of the inquiry, and see how it 
affects the point in question : for a difference which may 
be of no consequence in one investigation may be very 
important in another. Thus, the particular day and 
hour of witnessing a phenomenon may be of little conse- 
quence to a naturalist, while the time of witnessing an 
act may be of the utmost importance on a criminal trial. 

A common instance of this sophism is, where unim- 
peachable testimony, regarding an immediate compre- 
hension, is rejected, upon the ground that the witness is 
not a proper judge of the matter, the comprehension be- 
ing confounded Avith inferences that may be drawn from 
it, which are a very different thing. Any one who pos- 
sesses the use of his faculties, may be quite competent 
to prove what he apprehended, although it may require 
a person skilled in the subject to draw the proper infer- 
ences. ' 

3. The degree of probability or improbability is mate- 
rially mistaken, forming the sophism of varying proba- 
bility, of which there are four varieties. 

(«.) Exaggerating probability is, where we infer that 



Sec. 4.] Sophisms of Probability. 305 

the degree of probability is much greater than what the 
proof, in reality, establishes. It is frequently combined 
with the sophistical leap : a low probability is inferred 
to be very high, and then it is inferred to be a certainty. 

(b.) Diminishing probability is, where we infer that 
the probability is much less than has been shown j and 
it is the converse of the preceding fallacy. 

(c.) Exaggerating improbability is, where an improb- 
ability is shown, and we infer that it is much greater 
than the reality. It is the converse of the first. 

(d.) Diminishing improbability is, where an improb- 
ability is proved, and we infer that it is much less than 
the reality, which is the converse of the third. 

These fallacies are generally combined with each other, 
because the same desire which leads men to exaggerate 
one view of the subject induces them to diminish the 
contrary : and they are of frequent occurrence, because 
probability does not generally admit of accurate meas- 
urement, and its real character is not easily determined. 
A common instance of the combination is, where men 
embark in hazardous undertakings with a confident ex- 
pectation of success, because there is a slight probability 
in its favor, which they magnify into a very great prob- 
ability, while they equally diminish the probabilities of 
failure. So, favorite opinions, based on slight probabili- 
ties, are often held tenaciously, as being extremely prob- 
able, while the contrary, and really more probable, opin- 
ions are unhesitatingly rejected. 

Fallacies of this kind may arise either from mistaking 
the character of the probability in the first instance, or 
by draAving inferences from it, and then overlooking the 
character of the premise. 

Sophisms of probability are very prevalent, because 
they save the pain of suspense and the labor of further 
investigation, and because we are frequently obliged, in 
the ordinary business of life, to act upon strong probabil- 
ities as if they were certainties. Their influence is often 
increased by the Imagination forming vivid and agreea- 
ble pictures of what we desire to be true, and equally 
vivid, but repulsive, pictures of what we desire to be 
false. These erroneous representations excite strong 
feelings, which withdraw our attention from the weak 
points of the case, and confine it to what makes in favor 
of that which we desire to be true, whence the fallacy is 
frequently unsuspected. 



306 Aeeeeax.:::. [Chat. XIX. 

Piierent kinds of this class of fallacies are very 
quently combiued with each other. We adopt one prop- 
osition the more firmly, because the contrary is deemed 
so improbable, and conversely, while we frequently e 
gerate or diminish the real probabilities. A common in- 
stance of this combination is, the erroneous conclusions 
we form regarding our future lives or the results of our 
undertakings or designs. We can easily find facts which 
establish a probability that we shall five long, succeed in 
our principal undertakings, and secure permanent happi- 

33, as well as an improbability of the reverse. We are 
apt to overlook the possibly stronger probabilities which 
lead to a different conclusion, and to overcolor both sides 
of the picture. 

All fallacies of this class are frequently combined with 
paralogisms of comprehension, signs and testimony, with- 
out which they would often be detected by a full and ac- 
curate new of the whole case ; but when we overlook 
one side of it. and form an erroneous opinion of the oth- 
er, that may appear to be very probable which we should 
readily perceive to be the very reverse, if we viewed the 
matter aright. Those who purchased lottery tickt'- :- 
ten thought there was a great probability that they 
would draw a high prize, although it was quite clear to 
any person who carefully considered the matter for a fevr 
seconds, that the probability was all the other way, as 
the high prizes were very rare, and only an exception to 
the rule. So many satisfy themselves that they will act 
prudently, five long, resist temptations to vice, and enjoy 
prosperity. They overlook the fact that, owing to their 
character and circumstances, the probability is all the 
other wav : and the events turn out accordingly. 



CHAPTER XIX. 

OF ABEEEASTIE5, OF. FALLACIES OF EEEFXEVAXCT. 

5 1. Aberhavcies of Contt ?::•>". — X.vrore of this class of Fallacies. 
— (1) Irrelevant Illustration. — Legitimate Object, and Abas 
Illustration. — (2) Indefinite Terms. — Proper course of deali: a 
thisFalla: — Analogies. — Requisite :o validity of 

reasoning from A : — Freqnent Combination. — i Deciding 
'.aracter. — Distinction. — VThv this Aberrancy prevalent. — 
Frequent Combination. — (5) Deciding by Consequences. — Truth 



Sec. 1.] Aberranctes of Confusion. 307 

preferable to Error. — Distinction. — (6) Deciding by Motives. — Why 
these no Criterion of Truth. — Relation of Motives to Arguments. — ■ 
Frequent Combinations. — (7) Deciding by Appearances. — Fre- 
quent effect of this Aberrancy. — (8) Irrelevant Induction. — Why 
prevalent in Political Discussions. — (9) Irrelevant Empiricism. — 
Requisite to establish an Empiricism. — Frequent Combination. — 
(10) Irrelevant Objection. — Relation of Difficulties to sound Argu- 
ments. — Criterions. — Caution. — Proper mode of dealing with Ob- 
jections. — (11) Irrelevant Modification. — (12) Homonymous Ex- 
pressions. — Frequent Combination. — (13) Verbal Illusion. — Why 
prevalent. — Distinction. — (14) Illusive Contradiction. — Frequent 
Combination. — (15) Confounding Means and End. 

In these fallacies, one conclusion is assumed to be tan- 
tamount to another, while they are essentially different, 
and it is inferred that one has been proved, because the 
other may have been proved. The following enumera- 
tion includes the more common : 

1 . Irrelevant illustration consists in confounding mere 
illustrations with proofs. The legitimate object of illus- 
trations is, to throw light on a proposition which is 
proved and directly explained independently. Where 
all our knowledge of a subject is derived from illustra- 
tions, we generally form erroneous conceptions of the 
thing illustrated, and thus think we know what we only 
conceive. Where a thing entirely unknown is illustrated 
by something familiar, but not well understood, we are 
apt to think that we understand both, when we under- 
stand neither ; and consequently the mere illustration is 
mistaken for a proof that it is true, while no legitimate 
proof has been given. 

One of the most common foi'ms of this fallacy consists 
in drawing a comparison between the thing to be proved 
and something else, and then assuming that what is known 
to be true of the latter holds equally true of the former. 
Thus, communities have been compared to individuals, 
and it was then assumed that -they all have a period of 
youth, manhood, old age, and extinction. 

2. Indefinite terms occurs where obscure, ambiguous 
or figurative language is employed in such a manner that 
it is impossible to determine what it means ; and, there- 
fore, the conclusion actually established may be very 
wide of that which ought to be proved, if anything at all 
has been established. Where an essential part of an ar- 
gument consists of language whose exact meaning Ave 
cannot ascertain, it is impossible to determine whether 



308 Aberrancies. [Chap. XIX. 

any conclusion has been established : for the objection- 
able part may involve a fallacy : and consequently the 
-whole should go for nothing, so far as proving a conclu- 
sion is concerned. 

This fallacy abounds in various treatises on mental 
science. Loose generalities are substituted for definite 
statements ; and, in many instances, gross absurdities are 
veiled under misty plausibilities. 

3. Irrelevant analogies is, where an analogous conclu- 
sion is proved, which is assumed to establish the ques- 
tion, when, in reality, it does not. In order to render 
such argument valid, it must distinctly appear that the 
two cases are essentially alike, both in the conclusion and 
in all those points on which it depends : for, if they diner 
in these respects, other resemblances will avail nothing. 
It is not sufficient that they may resemble each other in 
these respects : it must appear that they actually do so : 
else the analogy may fail in some essential point. "We 
may err by assuming, without proof, either that things 
which are alike in some respects, are alike in others also, 
or that things which differ in some respects, differ in oth- 
ers also. 

A common instance of this fallacy is, proving some- 
thing of one man, and then inferring that this holds true 
of another, who resembles him in some resj^ects, while 
there is no proof that the similarity extends so far as it 
should do, in order to render the reasoning valid. Thus, 
one sick person's symptoms may resemble those of an- 
other, while their diseases may differ so widely that what 
cured one will only injure the other. So it has been ar- 
gued that popular education must be injurious, because, 
if a horse knew enough, he would throw his rider, while 
it is not shown (and, in fact, it is not true) that the rela- 
tion of a horse to his owner is the same as that of a peo- 
ple to their rulers. 

To this fallacy belongs the practice of applying gen- 
eral maxims to cases essentially different from those to 
which they properly apply, and thus drawing erroneous 
inferences regarding the case in question. This form is 
often combined with the paralogism of misinterpretation, 
the maxim being misunderstood, as well as misapplied. 
Other instances of this aberrancy are — assuming that the 
future will be like the past, and that a thing will never 
be, because it has been shown that it never was — assum- 



Sec. 1.] Aberrancies of Confusion". 309 

ing that a thing must be useful for one purpose, because 
it has been shown to be useful for another — assuming 
that a thing must be totally bad, and should never be 
used, because it is liable to be abused, or to produce evil 
— proving that a thing ought to be, and then assuming 
that it actually is, or that it ought not to be or that it 
would be useless, and then assuming that it is not — that 
a man will act in a certain way, because it is shown that 
ordinary prudence requires him to do so — and proving 
that there is no known reason why a conclusion should 
not be true, and then inferring that it is true, while there 
may be unknown proof that it is false. 

The aberrancy is frequently combined with the sophism 
of false cause, by assuming that, in the analogous case, a 
certain phenomenon resulted from a cause of which, in 
reality, it was wholly independent, and which is absent 
in the case under consideration. 

4. Deciding by character occurs where a conclusion is 
assumed to be true, because it is shown that it is advo- 
cated by good men, or alleged to be a good doctrine, or 
it is assumed to be false, because it appears that it is 
maintained by bad men, or it is alleged to be a bad doc- 
trine. Good men have often advocated errors, while bad 
men have held many opinions which were correct : and 
truth has frequently been decried as jDernicious, while 
error has been upheld as fostering virtue. Hence the 
truth or falsity of a proposition is a very different in- 
quiry from that of the character of its advocates, or its 
alleged nature ; and we wander from the point when we 
turn to discuss them, while the matter before us is, the 
professed proof that the proposition is true or false. 

In many cases the alleged character of the parties and 
nature of the proposition, are widely different from the 
real, so that the argument, besides being irrelevant, is 
otherwise fallacious. Yet, owing to the influence of sev- 
eral strong prejudices, its true character is not even sus- 
pected. It is pleasing to indolence to think that it can 
determine the truth or falsity of a proposition by merely 
glancing at the character of its advocates, which is as- 
sumed to be what is alleged by their friends or enemies : 
and it is soothing to the feelings to conclude that a doc- 
trine is true, when it flatters avarice, pride or vanity, and 
false, when it wounds these emotions. 

5. Deciding by consequences is, where certain good 



310 Aberraxcies. [Chap. XIX. 

consequences are held to flow from a doctrine, and therc- 
, fore it is inferred to be true, or, conversely, it is inferred 
to be false, because certain evil consequences are alleged 
to flow from it. A man sometimes finds that, if a cer- 
tain conclusion is true, he is bound to abandon some fa- 
vorite practice, or relinquish some lucrative occupation ; 
and, therefore, he is strongly disposed to reject such a 
doctrine, though it may have been proved quite conclu- 
sively, and, in fact, the difficulty which he encounters is 
in favor of the disagreeable conclusion. That it should 
militate against a vicious practice or a pernicious pur- 
suit, rather proves it true than otherwise. Yet the vic- 
tim is very unwilling to believe the bitter truth, although, 
in reality, the sooner he does so, the better for his own 
permanent welfare. 

Truth is always more favorable to happiness, in the 
long run, than error, although it may occasion some tem- 
porary pangs, or deprive us of some fleeting or fancied 
good. The world has yet to see the first instance in 
which a person did not gain much more than he lost by 
discarding error and adopting truth, while there are in- 
numerable instances in which men clung to errors, under 
the belief that the contrary doctrines were inimical to 
their hajDpiness, when, in reality, those errors destroyed 
their happiness, while the adoption of truth would have 
secured an opposite result. We should, therefore, ad- 
dress ourselves fearlessly to the proofs, while we are in- 
quiring whether a proposition is true or false. Its bear- 
ings on our future condition is a distinct question, which 
should never be allowed to interfere with the former. 

To this fallacy belongs the practice of pronouncing on 
the wisdom or folly of a certain course, according to the 
subsequent results. These may depend on circumstances 
which no human foresight could anticipate, and make a 
course afterwards seem foolish which previously appear- 
ed the most eligible. On the other hand, a very silly 
scheme sometimes produces favorable results, owing to 
accidental circumstances, which were not foreseen, and 
of which there was very little probability. 

6. Deciding by motives occurs where the conclusion is 
decided according to the motives which are alleged to 
actuate the advocate. A man may advocate the cause 
of truth from bad motives, or that of error from the re- 
verse, and hence motives are no criterion of the conclu- 



Sec. 1.] Abekkancies of Confusion. 311 

sion. In examining a man's general character, or the 
bearings of an act which he has done, the motives which 
influenced him may form a very pertinent and important 
subject of inquiry: but the truth or falsity of a propo- 
sition which he advocates is a very different matter. A 
conclusive argument is not a whit invalidated by being 
urged from bad motives, while a worthless argument is 
not in the least aided by the good motives of its pleader. 

A common instance of this aberrancy is, assuming that 
an argument must be worthless, because it is inconsist- 
ent with some other opinion expressed by the advocate, 
as if a good argument was refuted by the fact that its 
maintainer had formerly employed a bad one, or express- 
ed himself differently on the same subject. 

This fallacy is often combined with those of deciding 
by consequences and character. Certain bad conse- 
quences are alleged to follow from the conclusion, and it 
is asserted that the advocate must be a bad man, and 
therefore he must be influenced by bad motives, and 
therefore the conclusion must be false, or conversely. 
Possibly the supposed consequences are wholly imag- 
inary, or the individual may not see that they follow. 
Many hold opinions that really imply consequences which 
they neither see nor admit. Doctrines produce their le- 
gitimate consequences in the long run, on the majority 
of those who embrace them : but they do not always do 
so in the first instance, or in every individual case. 

Not imfrequently the aberrancy is combined with 
sophisms of causation and probability. The individual 
has, in reality, acted from several different motives, or 
those alleged are only probable, or perhaps wholly im- 
aginary, so that, in fact, no conclusion whatever is proved. 

7. It is shown that there are several indications which 
go to prove a certain conclusion, and it is inferred that 
it is absolutely proved, forming the aberrancy of decid- 
ing by appearances. It often escapes detection, partly 
owing to the influence of strong prejudices, and partly 
from the indications establishing a probability in favor 
of the conclusion. 

Instances of this fallacy occur where it is inferred that 
a certain person is a good man, because it has been shown 
that he professes to be, and is generally considered such, 
and that he has perfoi-med some good actions, while a 
wider and closer investigation would prove the reverse. 



312 Abekkancies. [Chap. XIX. 

So it is often inferred that a man is a bad character, be- 
cause he has been charged with having committed wick- 
ed acts, when, in truth, the charge is quite groundless, 
and the acts were harmless and proper; and, even if 
they were not, they would not prove the conclusion. 
Particular actions do not prove general character, any 
more than the latter prove the former ; nor does the per- 
formance of certain virtues and abstinence from certain 
vices, prove a man virtuous. 

8. Irrelevant induction is, where a thing is proved to 
hold true of numerous cases, and this is assumed to prove 
that it holds true of a whole class, when there is no proof 
to warrant such an inference, which is justified only by 
facts that logically involve it. Instances of this aber- 
rancy occur even in Mathematics, as where the binomial 
theorem had been assumed to hold true generally simply 
because it did so in many cases. It is very common in 
political discussions, since parties readily assume that 
what has been true, in several cases, will always hold 
true, where the assumption helps them in defending a 
weak position. 

9. Irrelevant empiricism is where a thing is proved of 
several individuals, and it is then assumed to apply to 
others, of which it has not been proved, and of which, 
possibly, it does not hold true. The satellites of the 
Earth, Jupiter and Saturn, all revolve round their prima- 
ries from west to east ; but some of Saturn's revolve in 
the contrary direction. To establish an empiricism, it is 
requisite that every individual object embraced in the 
conclusion, should have been examined, and found to pos- 
sess the attribute in question. 

The two preceding aberrancies are sometimes com- 
bined with each other, and with paralogisms of compre- 
hension. While the proposition in question is professed 
to have been established as an induction, a wider and 
more accurate observation would show that it is not true 
even empirically. Phrenology furnishes a good instance 
of this combination. Not only do its advocates fail to 
show that the alleged conformity between certain forms 
of the head and certain mental characteristics hold true 
generally, but they fail to prove that it has been hitherto 
found to hold true ; and careful observation will readily 
show that no such conformity exists, and that the cases 
of nonconformity arc much more numerous than those 
of casual conformity. 



Sec. 4.] Aberrancies op Confusion. 313 

10. Irrelevant objection occurs where it is shown that 
the proposition in question is liable to certain objections, 
or that difficulties attend its reception, whence it is in- 
ferred to be false, while, in reality, those difficulties nei- 
ther disprove the conclusion nor invalidate the argu- 
ments by which it is established. The alleged doubts 
or difficulties are generally founded on the objectoi''s 
vague or erroneous views of the whole subject, or at 
least of an essential part of it, and consequently possess 
no real weight. Difficulties attend every department of 
human knowledge : but they do not affect conclusive 
proofs. 

Sometimes the objection applies only to a misrepre- 
sentation of the proposition in question, made by a party 
who does not rightly understand it, and not to the real 
question. It is not uncommon for persons to defend doc- 
trines which they do not rightly understand ; and, there- 
fore, we should first ascertain what a proposition really 
is, before we regard objections, which may possibly ap- 
ply only to what it is erroneously represented to be. 

A common instance of this aberrancy is, where a prop- 
osition is argued to be false, because it is alleged to be 
inconsistent with some known fact, or to lead necessarily 
to some erroneous inference, when, in reality, such alle- 
gations are quite irrelevant. Sometimes they are false, 
and, in other cases, although true, they are, in reality, 
quite consistent with the proposition in question. 

A sound argument can no more be inconsistent with 
any truth than one truth can be incompatible with an- 
other. If, therefore, the objection conclusively proves 
that the proposition in question cannot possibly be true, 
it is sound, but otherwise not. It avails nothing that it 
establishes a strong probability against it, if this is rebut- 
ted by conclusive evidence, or even by a stronger prob- 
ability on the other side. If the proof in favor of the 
proposition is conclusive, every objection must evidently 
be futile, and should go for nothing. 

In no case should we reject as invalid a proof which 
appears to be quite the reverse, till we have given or ob- 
tained a demonstration of its fallaciousness. Sometimes 
we may think this is attainable, when a serious attempt 
to find it would show us that the objection is worthless, 
and the proof irrefragable. It frequently happens that 
the proof exhibits something which is objectionable, but 
O 



314 Abekkancies. [Chap. XIX. 

which does not affect its substantial validity, as where 
something false is assumed in an argument which does 
not affect its soundness, and may, in fact, be a mere illus- 
tration. Yet the objector is apt to fasten on the flaw, 
and hold it forth as conclusive. We should, therefore, 
observe the relation of the objectionable part to the 
whole proof, and ascertain whether the objection is not 
irrelevant, even admitting that its primary premises are 
quite true. 

11. Irrelevant modification consists in proving a prop- 
osition which is a modification of the one in question, 
but yet materially different. A common instance of it 
is, where a conclusion is proved conditionally, when it 
ought to have been proved absolutely. Thus jurists 
have sometimes professedly shown that a particular form 
of government was the best for a particular nation, and 
then assumed they had proved it is the best for every 
nation. So it is sometimes assumed that a certain regi- 
men or medical treatment is best for everybody, because 
it has been shown to be the best for persons of a partic- 
ular constitution; and many lives have been thus lost. 
Another instance is, showing that a certain law, institu- 
tion, or custom had a rational origin, and then assuming 
this as proving that it is good universally, while, in fact, 
it may be very bad when circumstances have greatly 
changed. 

12. Homonymous egressions consists in proving a 
proposition which sounds very like the one in question, 
and may be readily mistaken for it, while it is essentially 
different. It is favored by the fact that many words and 
expressions are very similar in sound, but yet materially 
different in signification. A man may do many foolish 
things without being a fool, and many good things with- 
out being good. This aberrancy is often combined with 
the preceding; and the combination occurs not unfre- 
quently in public addresses. Thus, a speaker proves that 
everybody within a certain narrow circle thinks or does 
so and so ; and this is assumed as proving that all man- 
kind do so. 

13. Verbal illusion occurs where the name of a thing, 
or a definition of it, is given, and this is assumed to be 
tantamount to communicating or acquiring a knowledge 
of its nature. We are very ready to adopt this fallacy, 
because the name is apt to be confounded with the char- 



Sec. 1.] Aberrancies op Confusiok. 315 

acter, and it is so much easier to master the former, or 
read a definition, than to acquire a real knowledge of the 
latter. Thus, many have thought that they had acquired 
a good knowledge of Botany, when it went no farther 
than to enable them to tell the name of a genus. So 
teachers have often thought that they communicated to 
their pupils a knowledge of the subject, when they only 
taught them words whose real import they never under- 
stood. Words can convey no real instruction unless 
their import is properly understood and remembered, 
which is a very different thing from merely hearing or 
reading and repeating them. 

14. Illusive contradiction consists in confounding the 
contrary of a proposition with its contradictory, and it is 
inferred that it is true, because its contrary is shown to 
be false. Thus, it is often assumed that a thing is bad, 
because it has been proved that it is not good, or that a 
certain line of conduct is commendable, because the con- 
trary course is reprehensible, as if the sky must be white, 
because it is not black. So it is often assumed that a 
man is austere, because he is not gay, or penurious, be- 
cause he is not extravagant, or rash, because he is not 
timid, and so forth. 

The fatalists' argument is a notable example of this 
aberrancy. "A thing will either happen or not," and 
this is confounded with " happening if I act thus, and not 
happening if I act otherwise." When a man's house is 
on fire, the real question is, whether his efforts will affect 
the result ; and this is not, in the least met, by saying 
that it is destined either to burn or not to burn, which 
is only saying that it either will burn or it will not, a 
self-evident truth, indeed, but quite irrelevant. 

Another instance of this fallacy is, confounding " be- 
lieving" with "not disbelieving." As we must either 
believe or not believe, it is assumed that we believe 
everything which we do not formally disbelieve, whereas 
we have no real belief or disbelief in a thing of which we 
are ignorant. Confidence in a man's veracity is a very 
different thing from believing his opinions, which we 
cannot do till we know what they are. 

This aberrancy is frequently combined with the soph- 
ism of false connection. Because a conclusion does not 
follow from the premises, it is inferred, not only that it 
is false, but that the contrary is true. Thus, a contro- 



316 Aberrancies. [Chap. XIX. 

versialist often assumes that his own position is proved, 
because he has detected a flaw in some reasoning em- 
ployed to prove the contrary conclusion. The compound 
fallacy is of this sort: "this reasoning fails to prove that 
crows are black ; therefore they are white." To war- 
rant us in receiving a proposition as true, it is not suffi- 
cient to disprove certain arguments employed to prove 
the contrary doctrine : Ave must have positive and con- 
clusive proof that it is true. For the contrary proposi- 
tion may be provable by other arguments, or both prop- 
ositions may be false. 

15. Confounding means and end consists in proving 
that the end or object to be effected by certain means, 
is good, and then assuming that the latter are good. A 
proper end may be sought by wrong means, of which 
numerous cases are found both in History and. common 
life. Consequently the character of the means must be 
ascertained, on other grounds than the goodness of the 
end. In many instances, the object is really bad, and 
only supposed to be good : but the fallacy is not the less 
complete, even where it is really good. Fraud is unjus- 
tifiable when it is employed to propagate truth, as well 
as when it is used to sustain error. 

§ 2. Aberrancies op Appeals to Authority. — Nature of this 
Class. — (1) Universal Belief. — Why not conclusive Proof. — (2) 
General Belief. — (3) Conflicting Opinions. — Its Foundations. — 
(4) Modern Opinions. — Why not Proof. — (5) Sages' Opinions. — 
Distinction. — Sources of Error. — Frequent Combination. — (G) 
Many Arguments. — Distinction. — Various Forms. — (7) Pretended 
Refutation. — Proper mode of dealing with Refutations. — (8) Ir- 
relevant Admission. — Its Characteristic. — Frequent Effect of it. 
— With what often combined. — Why Aberrancies of this class arc 
common. — How to be avoided. — Important Distinctions. 

In this class of aberrancies, it is shown by others, or 
is found by ourselves, that certain persons have believed 
the proposition in question, which is considered tanta- 
mount to proving that it is true, while, for anything that 
appears to the contrary, it may be false. The following 
are the most common kinds. 

1. Universal belief occurs where a conclusion is either 
assumed to be true, because it is found that all mankind 
have believed it, or it is assumed that it must be false, 
because it appears that all mankind have disbelieved it. 
There may be various sources of illusion, common to all 



Sec. 2.] Appeals to Authority. 317 

mankind ; and hence universal belief is by no means a 
conclusive proof that a proposition is true. All mankind, 
for many ages, believed things self-evidently or demon- 
strably false, and rejected as false things self-evidently 
or demonstrably true. We uniformly believe that our 
dreams are real, till we awake, when we discover the 
contrary. So it was universally believed, for many ages, 
that the Sun, Moon, and stars revolve daily round the 
Earth, while the doctrine that the Sun is at rest, and the 
Earth in motion, was rejected as an absurdity. 

2. General belief is, where we infer that a proposition 
is true, because it appears that the great majority of man- 
kind have believed it, in all ages. If universal belief does 
not prove a proposition true, much less will the belief of 
a majority only, especially when we consider how fre- 
quently and readily opinions are adopted without any 
proper investigation. It has been a generally received 
opinion that seeds germinate more quickly during the 
crescent Moon than when it is in the wane ; yet a very 
slight investigation shows that it is quite groundless. 

3. Conflicting opinions consists in inferring that a 
proposition is doubtful, because it appears that different 
opinions are held regarding it, when its truth may have 
been conclusively established. This aberrancy proceeds 
on the absurdities that any man's views are as likely to 
be correct as any other's, and that we cannot be certain 
a conclusion is true, as long as there is anybody so ig- 
norant, indolent, stupid or prejudiced as to reject it. 
Where we have unquestionable proof that it is true, the 
opinions of such persons to the contrary are entitled to 
no weight. 

4. It is inferred that a proposition is true or false be- 
cause it appears to be deliberately held or rejected by 
the men of the present day. This we call the aberrancy 
of modern opinions. No age is exempt from error ; and 
it has sometimes happened that old opinions have been 
re-adopted, on good grounds, after having been long re- 
jected. The astronomical opinions of Aristarchus of Sa- 
mos were rejected by all astronomers, for nearly two 
thousand years ; yet they have been demonstrated to be 
correct. 

5. Sages'* opinions occurs where it appears that wise 
or distinguished men held a certain opinion, and, there- 
fore, it is inferred to be correct, although there may be 



318 Aberrancies. [Chap. XIX. 

positive proof to the contrary. History furnishes innu- 
merable iustances in which such men, who were consid- 
ered guides, held conflicting views, or opinions which 
were afterwards demonstrated to be quite erroneous. 
We must distinguish between testimony, regarding mat- 
ters which can be certainly known, and mere opinions, 
which are generally based only on probabilities. An 
unimpeachable witness may be safely believed, when he 
relates something within his knowledge : but this does 
not, in the least, warrant us in adopting his mere opin- 
ions as ascertained truths, especially where there may be 
accessible proofs that they are quite erroneous. 

Distinguished men are sometimes as much under the 
influence of prejudices as any others : and a person of or- 
dinary abilities, who examines a subject carefully and im- 
partially, will often arrive at truth, where men of greater 
talents err, through inattention, haste or prejudice. A 
conceit of their own abilities has often injured such per- 
sons, in the pursuit of truth, more than their intellectual 
superiority benefited them. In all the most important 
investigations, the great requisites are, attentive, unprej- 
udiced and persevering examination, with a fixed desire 
to discover truth. For the want of these, neither a great 
reputation nor brilliant talents will, in the least, compen- 
sate. 

This aberrancy is often combined with those of mis- 
comprehension and misinterpretation of language. A 
person's real views are mistaken or misinterpreted ; and 
then his authority is adduced to support opinions which 
he never held. Thus, the usages of our ancestors are oft- 
en quoted to support or oppose some proposed change. 
As our ancestors' circumstances were very different from 
ours, their actual usages form no criterion of what they 
would have done, in our circumstances. It is not likely 
that our pagan forefathers would discard revealed relig- 
ion, if placed in our circumstances. Time produces many 
changes, so that what is eligible in one generation may 
be the reverse in another. So it is frequently maintain- 
ed that the experience of competent judges has already 
decided the question, when the thing really experienced 
is essentially different. It was once believed the expe- 
rience of intelligent surgeons proved that scalding oil is 
useful in dressing wounds, whereas it is now well known 
that it proves the reverse. 



Sec. 2.] Appeals to Authoeitt. 319 

6. It appears that the point in question is sustained by- 
various arguments, whence it is inferred that it is duly- 
proved, forming the aberrancy of many arguments. No 
number of arguments can prove a conclusion, as long as 
every one of them is invalid ; and many such have been 
employed to prove false conclusions, of which the Ptole- 
maic Astronomy and the Aristotelian philosophy furnish 
various instances. We should remember that, as in the 
case of witnesses, it is the weight of arguments that 
avails, and not their number : while one conclusive argu- 
ment proves a proposition, beyond any reasonable doubt, 
a thousand fallacious arguments establish nothing. Yet 
this fallacy has often produced conviction, because its 
victims, while possibly distrustful of the particular argu- 
ment under consideration, relied on the combined force 
of the others, and so on, in an endless round. 

f I. Pretended refutation is, where an argument and the 
conclusion based on it, are rejected, because they have 
been professedly refuted, when, in reality, the refutation 
is fallacious. It is often added that the conclusion in 
question is an exploded opinion, which nobody but very 
ignorant or silly persons now hold. In many instances, 
the argument is grossly misrepresented, and nothing is 
refuted but what was never held, or something essential- 
ly different from the matter in question. Sometimes the 
refutation is directed against the fallacious arguments of 
an ignorant or incompetent advocate, and never touches 
the real proof. At other times, the main parts of the ar- 
gument are overlooked, while a few immaterial errors are 
detected ; and this is assumed to be a complete refuta- 
tion. Consequently we should examine the argument, 
and compare it carefully with the professed refutation, 
before we receive the latter as of any weight. Error 
never appears more clearly in its true character, than 
when it has had a fair hearing and a searching examina- 
tion. 

8. It appears that a certain conclusion follows from 
premises admitted by a party who denies it, whence it is 
inferred that it must be true, forming the aberrancy of 
irrelevant admission. It is perfectly fair to argue that 
a man is bound to admit a conclusion necessarily implied 
in premises which he admits or believes : the fallacy lies 
in assuming that the conclusion has been established ab- 
solutely, while the admitted premises may be false. If a 



320 Abekranctes. [Ciiap. XIX. 

man admits that the main object of public punishments 
is, the reformation of the offender, he admits, by neces- 
sary implication, that capital punishments are wrong ; 
but this admission is false, the reformation of the offend- 
er being only a secondary object in public punishments, 
although it is often the sole object of private chastise- 
ment. 

This fallacy has sometimes confirmed controversialists 
in their errors. The opposite party made admissions 
"which proved their tenets ; and they never saw or sus- 
pected that those admissions were un warrantable. The 
aberrancy is often combined with the paralogism of mis- 
representing testimony. A man's admission or expressed 
belief is misrepresented ; and then it is assumed that the 
consequences necessarily implied in the misrepresentation 
are established absolutely and conclusively. 

Fallacies of appeals to authority are very prevalent, on 
account of the greater ease and pleasure with which a 
conclusion can generally be settled by such appeals, in- 
stead of being decided by a proper investigation of proofs, 
while numerous strong prejudices often intervene, and 
rivet the error. The proper course is, to ascertain wheth- 
er there is conclusive proof of the truth of the proposition 
in question. If there be, it must stand, although high 
authority reject it: if there be not, it has no good title 
to be classed with cognitions, and it may possibly be 
false, no matter who believe the contrary. 

Preponderating authority may be very properly made 
our guide where certainty is unattainable, and we can 
arrive only at probabilities : but mere human belief can 
never prove any proposition, because it is never exempt 
from error. We should not, therefore, confound the ques- 
tion whether the proposition under consideration is true, 
with the very different inquiry what others have thought 
of it, as is generally done by those who are misled by this 
class of fallacies. To establish or refute a proposition by 
legitimate proof, is a very different thing from showing 
that men have believed it to be true or false. 

§ 3. Aberrancies of Appeals to Desires. — Nature of this Class. 
— (1) Inferring the Agreeable. — Its operation. — Distinction. — (2) 
Rejecting the Disagreeable. — Frequent Practices. — Sneers and Rid- 
icule. — Distinction. — Combination. — How these Fallacies are fos- 
tered. — Their two-fold Origin. — Their Influence and general Char- 
acter. — llow combined. — Uow they may be avoided. 



Sec. 3.] Appeals to Desires. 321 

Here the proposition in question excites strong emo- 
tions or sensations, whence it is inferred that it is true or 
false, while its real character is not properly, if at all, in- 
vestigated. Of this class there are two kinds. 

1. A conclusion becomes very agreeable, and it is thence 
inferred that it is true, forming the aberrancy of infer- 
ring the agreeable. Here the facts or arguments that 
militate against the conclusion are seldom considered 
with any degree of attention : they are sometimes dis- 
missed with a sneer or a sarcasm; and sometimes they 
are not noticed at all. In many cases the proposition in 
question is merely characterized by eulogistic epithets, 
and its adherents are called by corresponding terms, 
whence it is assumed to be true. There is no error to 
which the strongest terms of commendation cannot be 
easily applied, while there is no truth to which the most 
opprobrious epithets cannot be applied, with equal fa- 
cility. 

A common and pernicious instance of this fallacy is, 
inferring that the course which promises present enjoy- 
ment and immunity from present pain, is the best, when 
the case may be far otherwise ; and thus many have sac- 
rificed their future all for a fleeting present gratification. 
The notion of enduring present pain, or foregoing pres- 
ent pleasure, is so disagreeable that they assume the fu- 
ture is of less importance ; and the excitement withdraws 
the attention from a careful consideration of it. 

Another common instance is, where it appears that we 
shall gain wealth, ease, distinction, the approbation of 
friends, or the patronage of the powerful, if we believe 
the proposition in question, and it is assumed that, there- 
fore, it is true. Although such inducements tend to pro- 
duce conscious hypocrisy, rather than real belief, yet it 
has frequently caused conviction, the prejudices excited 
having confined the attention to one aspect of the sub- 
ject, and concealed its true bearings. But the advant- 
ages to be dei'ived from believing a proposition are a to- 
tally different thing from its truth or falsity, with which 
they ought never to be confounded. 

2. Something appears which renders a conclusion dis- 
agreeable, whence it is inferred to be false, forming the 
aberrancy of rejecting the disagreeable. It is simply the 
converse of the preceding fallacy ; and the same remarks 
apply to both, by merely reversing the terms. Some- 

02 



322 Aberkancies. [Chap. XIX. 

times the proposition in question is held up to ridicule, 
and called by offensive or contemptuous epithets, and 
then it is assumed to have been proved false, a course 
which has often imposed on the unthinking, who seem to 
believe that an argument can be refuted by a simple ex- 
clamation of scorn or ridicule. 

The strength of the language in which the conclusion 
is decried, generally increases as the evidence of its truth 
becomes clearer. When a man is too prejudiced to yield 
to testimony or arguments, which prove that his conduct 
or opinions are wrong, he frequently stifles his convic- 
tions or suspicions by a free use of ridicule or abusive 
language. But, for the reason already mentioned, these 
have no logical force ; and they are generally employed 
by those who can adduce no valid proof in support of 
their own opinions, or against their opponents'. 

A frequent instance of this aberrancy is, where it ap- 
pears that a person will undergo serious loss or suffer- 
ing, if he disbelieves a certain proposition, or adopts the 
contrary, and, therefore, it is inferred that it is false. This 
result has frequently been produced seemingly, and some- 
times really, by means of imprisonment, corporal chas- 
tisement, torture, loss of situation, or disapprobation of 
relatives and friends. 

This aberrancy is generally combined with the preced- 
ing, and the combination has frequently imposed upon 
the weak-minded, the ignorant, and the unprincipled. 
The advantages held out, on the one hand, and the dis- 
advantages either threatened or actually inflicted, on the 
other, have produced, in countless millions, belief in dog- 
mas which they might easily have ascertained to be to- 
tally false. 

Fallacies of appeals to desires are greatly fostered by 
the perfect ease with which they can be used. To pro- 
duce facts or substantial arguments for or against a prop- 
osition, requires time and labor, while it is always very 
easy to call it by laudatory and pleasing epithets, on the 
one hand, or by offensive and contemptuous terms, on 
the other. The former indirectly imply that it is so well 
established otherwise, or so perfectly evident, that more 
formal proof is not required, or, conversely, that it is so 
absurd, or so conclusively refuted already, that no elab- 
orate argument is now required to disprove it, while, for 
anything that appears to the contrary, the truth may be 
the very reverse. 



Sec. 3.] Appeals to Desires. 323 

These aberrancies are very apt to escape detection in 
public addresses, because the strong feelings excited by- 
mutual sympathy between all present, both speaker and 
hearers, concentrate the attention on certain points, and 
withdraw it from others, so that the worthlessness of the 
argument is overlooked, although, in many cases, the 
slightest analysis of it would readily show that it proves 
nothing at all. 

Such fallacies are not only employed by others, to mis- 
lead us, but we are very liable to fall into them, in our 
own oi-iginal investigations, since our minds tend toward 
the agreeable, and against the disagreeable, without any 
prompting from others : and indeed this native tendency 
is requisite, in order to effect extraneous imposition by 
such means, which are rarely effectual, except where we 
are prepared to adopt them. 

Fallacious appeals to desires have been one of the prin- 
cipal means of propagating and riveting error, in every 
age and country. They are so numerous that it would 
be tedious to describe the various species in detail ; and 
they are all so similar in their operation, and run so much 
into each other, that such a description would be of little 
use. The most common and pernicious are those which 
relate to religious, ethical and political matters ; and the 
two kinds are generally combined, the one side being de- 
picted as very attractive, in order to secure an easy be- 
lief, and the other represented as quite repulsive, in order 
to deter scrutiny. 

These aberrancies, however, are generally combined 
with fallacies of comprehension, testimony, probability, 
or appeals to authority, without which their influence 
would be comparatively small, since all know that wish- 
es are not proofs. Sometimes the facts are first misrep- 
resented ; then a probability is established on this foun- 
dation ; then this is attempted to be fortified by falla- 
cious appeals to authority ; and, finally, friendly and hos- 
tile passions are excited, to secure the reception of the 
error. In other cases, some of these processes are omit- 
ted, or the order of arrangement is reversed, the oppos- 
ing views being rendered odious or contemptible in the 
first instance, by being grossly misrepresented. 

As in the case of the simple aberrancy, we may mis- 
lead ourselves by such combinations, as well as be misled 
by others. Thus, we often form a very erroneous opin- 



Abkrraxcies. [Chap. XIX. 

ion regarding the character, condition and position of 
ourselves, our friends, denomination, or country. A> it 
is pleasant to think well of ourselves, and unpleasant to 
think otherwise, Ave look at the bright side of our own 
characters and at the dark side of others, while we exag- 
gerate both ; and thus we easily find probabilities in fa- 
vor of our own superior excellence, and improbabilities 
against our being in the wrong, while, on the other hand, 
we find, with ecpial facility, probabilities that others are 
in the wrong, where they differ from us, and improbabil- 
ities that they are right. Our opponents or neighbours, 
by reversing the proceeding, and looking at their own 
bright side and our dark side, readily arrive at an oppo- 
site conclusion. 

Such combinations have fostered selfishness, pride, na- 
tional or sectarian animosities, and an obstinate persist- 
ence in wrong courses. Thus, we often flatter ourselves 
that we Avould act much better than others have done, 
if we were placed in their circumstances, because we mis- 
take the nature of these, and form erroneous judgements 
regarding the mode in which we have acted, when placed 
in similar circumstances. If we corrected these errors, 
we might find that our superiority is wholly imaginary. 

Combinations like the preceding are sometimes aided 
by the production or presence of apprehensible objects. 
The production of a bloody knife has sometimes led to 
the condemnation of the accused, where there was no 
satisfactory proof of his guilt : and the sight or smell of 
liquor has often convinced a reformed drunkard that a 
glass would do him good, a few minutes after he was 
rightly of the contrary opinion. Sometimes the same ef- 
fect is produced by broad allusions, which strongly affect 
the Memory or Imagination of the party addressed. 

Fallacies of this kind are to be avoided by laying aside 
desires, and addressing ourselves attentively to the proofs, 
either for or against the conclusion. We must disregard 
both adulation and vituperation (which are generally used 
only by the advocates of error), and examine the proof 
with due care and attention. When we have ascertain- 
ed where truth lies, then, and not before, it is proper to 
give way to the feelings which it inspires, and to desig- 
nate doctrines and opinions by what we know to be their 
true character. 



Chap. XX.] 



Paralogisms. 



CHAPTER XX. 

TABLE OF FALLACIES. 



325 



I. Paralogisms. 



1. Paralogisms of Intuition 

2. Assuming what is attempted to 

be proved 

3. Paralogisms of Comprehension 



{ (1.) Intuitional assumption. 
\ (2.) Intuitional rejection, 
f (1.) Assuming the question. 
( (2.) Eeasoning in a circle. 

f (1.) Miscomprehension. 
I 1 



4. Paralogisms of Signs 



5. Paralogisms of Memory 



6. Intrinsic paralogisms of 
Testimony 



(2.) Incomprehension, 
j (1.) Illusive sign. 
( (2.) Non-interpretation of signs. 
( (1.) Imaginary apprehension. 
J (2.) False association. 
j (3.) Mistaking ideas. 
[(4.) Forgetfulness. 
(1.) Ambiguous expression. 
(2.) Overlooking conditions. 
(3.) Assuming conditions. 
(4.) Obscure expression. 
(5.) Wrong expression. 
(6.) Falsehood. 
(7.) Suppressing truth. 
(8.) Misrepresenting comprehensions. 
^(9.) Misrepresenting testimony. 
(1.) Adopting a mean. 
(2.) Counting witnesses 
7. Extrinsic paralogisms of J (3.) Credulity. 
Testimony )(4.) Scepticism. 

(5.) Overlooking testimony. 
(6.) Indiscrimination. 
(1.) Misunderstanding archaisms. 
(2.) Misinterpreting technicalities. 
(3.) Misinterpreting ambiguities. 
(4.) Confounding different senses. 
(5.) Overlooking the idiom. 
(6.) Following etymologies. 
(7.) Mistaking the style. 
(8.) Misplacing the accent. 
(9.) Misconstruction. 
(10.) Mistaking expressions. 
(11.) Ignorant interpretation. 
(12.) Misconception. 
(13.) Fallacious implication. 
(14.) Mistaking allusions. 
^(15.) Fallacious propriety. 



8. Misinterpreting Language < 



326 



Table of Fallacies. [Chap. XX. 



II. Sophisms. 



1. Sophisms of Confusion 



2. Sophisms of Ceneraliza 
tion 



3. Sophisms of Causation 



4. Sophisins of Proba- 
bility 



(1.) Sophistical connection. 
(2.) Inferring the converse. 
(3.) Altering propositions. 
(1.) Sophistical extension. 
(2.) Sophistical inclusion. 
(3.) Sophistical contraction. 
(4.) Sophistical exclusion. 
(5.) Sophistical combination. 
(G.) Imaginary universality. 
(1.) False cause. 
(2.) False effect. 

(3.) Confounding cause and effect. 
(4.) Hypothetical causes. 
(5.) Mistaking the chief cause. 
(6.) Mistaking the chief effect. 
(7.) Mistaking the ultimate cause. 
(8.) Sophistical explanation. 
(9.) Sophistical induction. 
(10.) Sophistical proof. 
(11.) Sophistical relation. 
(12.) Excluding causes. 
(13.) Excluding effects. 
(14.) Imaginary effect. 
^(15.) Imaginary cause. 
'(1.) Inferring the probable, including 
(a.) Inferring hypotheses, 
(6.) Accumulating probabilities, 
(c.) Friends' opinions, 
(d.) One-sided arguments, 
(e.) Harmonizing conclusions, 
(f.) Contingent connective, 
(ff.) Incomprehensible connective, 
(A.) Inconclusive investigation, 
(i. ) Sophistical leap. 
(2.) Rejecting the Improbable, including 
(a.) Discordant opinion, 
(6.) Overlooking the alternative, 
(c.) Rejecting theories, 
(d.) Severing probabilities, 
(e.) Enemies' opinions, 
(/.) Mortifying proofs, 
(ff.) Imaginary absurdity, 
(A.) Sophistical distinction. 
(3.) Varying probability, including 
(a.) Exaggerating probability, 
(6.) Diminishing probability, 
(c.) Exaggerating improbability, 
,_(</.) Diminishing improbability. 



Chap. XX.] 



Aberkancies. 



327 



III. Abekrancies. 

(1.) Irrelevant illustration. 
(2.) Indefinite terms. 
(3.) Irrelevant analogies. 
(4.) Deciding by character. 
(5.) Deciding by consequences. 
(6.) Deciding by motives. 
(7.) Deciding by appearances. 
1. Aberrandes of Confusion -^ (8.) Irrelevant induction. 
(9.) Irrelevant empiricism. 
(10) Irrelevant objection. 
(11.) Irrelevant modification. 
(12.) Homonymous expressions. 
(13.) Verbal illusion. 
(14.) Illusive contradiction. 
^(15.) Confounding means and end. 
'(1.) Universal belief. 
(2.) General belief. 
(3.) Conflicting opinions. 
(4.) Modern opinions. 
(5.) Sages' opinions. 
(6.) Many arguments. 
(7.) Pretended refutation. 
^(8.) Irrelevant admission. 



2. Aberrandes of Appeals to 
Authority 



3. Aberrandes of Appeals to 
Desires 



( (1.) Inferring the agreeable. 
( (2.) Eejecting the disagreeable. 



PART IV. 

A SPECIAL SUEVEY OF THE PRINCIPAL BRANCHES 
OF KNOWLEDGE. 



CHAPTER XXI. 

CLASSIFICATION OP KNOWLEDGE, ACCOEDING TO ITS 
SUBJECTS. 

§ 1. Scientific Knowledge. — Knowledge General or Particular. — 
Definition of Science. — Requisites to a Science. — What determines 
its Boundaries. — When new Sciences may be formed. — Three 
Classes of Sciences. — I. Subjects of Mathematics. — Analysis and 
Geometry. — Subdivisions of each. — Distinction. — II. Subjects of 
the Physical Sciences. — Their relation to Mathematics. — Their Di- 
visions. — (1) Subjects and Subdivisions of the Mechanical Sciences. 
—(2) Of the Ethereal.— (3) Of the Organical.— (4) Of the Geo- 
graphical Sciences. — III. Subjects of the Mental Sciences. — (1) 
Logic— (2) Psychology.— (3) Theology.— (4) Morality.— (5) Ju- 
risprudence. — Its Subdivisions. — Distinction. 

In regard to its nature, all knowledge is either gener- 
al or particular. The former comprises — (1) all cogni- 
tions which hold true of a whole class, as " the three 
angles of a triangle are equal to two right angles" — " the 
lion is carnivorous" — (2) those which express a fact that 
does not materially vary for ages, as " the Earth is about 
96 millions of miles from the Sun" — "the Nile flows 
northward into the Mediterranean" — and (3) those which, 
although they may be essentially particular, affect a 
whole class, as "Adam was the progenitor of all man- 
kind." The latter class includes — (1) cognitions express- 
ing things which materially change, from age to age, as 
" the population of London is about three millions" — and 
(2) those which express particular occurrences, as " Na- 
poleon Bonaparte died in 1821." The former class may 
be called scientific, as general cognitions form the main 
and essential part of every science, and other facts are 
employed only for the sake of proof and illustration, or 
to guide future researches regarding points not yet as- 
certained. 

A science is, a systematic body of general truths, re- 
lating to an important subject. To render a branch of 
knowledge a science, it must possess the following char- 
acteristics. 

1. Its propositions must be general: for a series of 
particular facts cannot evidently form a science. 



332 Classification of Knowledge. [Ciiap. XXI. 

2. These propositions must be so numerous as to form 
a body of knowledge : for a few propositions can no 
more form a science than a few sticks and stones can 
form a house. 

3. The truths must be real cognitions, and not merely 
believed, or fallaciously argued, to be such. True science 
always consists of things which are known by immediate 
discernment, satisfactory testimony, or conclusive infer- 
ences from unobjectionable premises. 

4. The truths must be arranged according to some 
principles of classification, so that a person ignorant of 
the subject can master the whole, as it is laid down, pro- 
vided he possesses ordinary faculties, and the requisite 
preparatory knowledge. The best materials, thrown to- 
gether without order or connection, are no more a science 
than a heap of building materials is a house. 

5. The subject must be important, either intrinsically 
or for its bearings on other subjects: else it would be 
unworthy of notice. 

6. The cognitions must be distinguishable from those 
of other sciences : else there would be no occasion to 
class them separately. 

7. The truths must all relate to one general subject, or 
to closely kindred subjects : otherwise the materials 
would be incongruous, whence would result confusion, 
obscurity, and error. 

The boundaries of a science are determined partly by 
the nature of the subject, and partly by the objects which 
it aims at effecting. It should embrace every important 
cognition strictly belonging to its subject, and having no 
close relation to any other. But, in some cases, cogni- 
tions are related, in nearly equal degrees, to two or thi*ee 
sciences : and here we should be guided by the rule that 
they ought to be placed as the interests of study require. 
They should be so arranged as to render the attainment 
and retention of knowledge as easy as possible. 

Inductions which do not properly belong to any exist- 
ing science, and are too few in number to constitute a 
separate one, should be classed with that to which they 
bear the closest affinity : and when a sufficient number 
of them has been established, they should be formed into 
a new science. So, when some subdivision of a science, 
which is of a distinct nature, has become extensive, it 
should be classed as a separate science. But this course 



Sec. l.J Scientific Knowledge. 333 

is not desirable simply because the subject may have be- 
come very extensive : for it would separate from each 
other things which are all parts of one closely connected 
whole. 

The sciences consist of three classes, the mathemat- 
ical, the physical and the mental, the subjects and divis- 
ions of which are as follows. 

I. The mathematical sciences treat of the relations and 
properties of abstract quantity. As this consists of num- 
ber and magnitude, Mathematics consist of two corre- 
sponding parts, Analysis and Geometry, the former of 
which treats of numbers, and the latter, of magnitudes. 

Analysis employs various symbols or signs, some of 
which express quantities — as 1, 2, 3, a, b, x, y, z — and oth- 
ers express the relations of quantities, or the operations 
to be pei-formed on them — as +, — , x , =, <, -\/ . It is 
of two kinds, Special, where the symbols have all a spe- 
cial signification, — as 1, 2, 3 — and General, where these 
have a general signification — as a, b, x, y. The former 
is commonly termed Arithmetic, and the latter, Algebra. 

Algebra is subdivided into the Elementary and the 
Higher. The former employs only constants, or symbols 
and functions which have but one value throughout the 
processes or operations in which they appear : the latter 
employs variables, or symbols and functions which vary 
in value in the same expression or operation, while the 
different values are frequently indefinitely, or, as it is oft- 
en expressed, infinitely small. 

Geometry treats of the four kinds of magnitude, lines, 
angles, surfaces and solids, the mathematical signification 
of which differs from the physical. The former includes 
only the various forms of pure extension, and excludes 
all conception of material substances. Thus, a physical 
line has always some breadth and thickness, but a math- 
ematical line has none. Geometrical magnitudes are rep- 
resented to our apprehension, however, by physical sym- 
bols, which greatly assist us in studying the science. 

Geometry consists of two parts — Synthetical or Pure, 
which treats of its objects directly, without the aid of 
Analysis — and Analytical or Algebraic, in which the 
propositions are investigated by means of Analysis. 
The latter represents the magnitudes by numerical quan- 
tities, while the former represents them directly. 

Analytical Geometry is subdivided into Determinate, 



334 Classification of Knowledge. [Chap. XXI. 

which discusses problems that admit only of a limited 
number of solutions, and Indeterminate, which treats of 
problems that admit of an indefinite number of solutions. 
In the former, the symbols which represent the unknown 
quantities have only one or a few values, while, in the 
latter, they vary indefinitely, and consequently it enables 
us to discuss the general properties of geometrical quan- 
tities. 

II. The physical sciences treat of physical or material 
nature, including whatever is directly cognizable by our 
senses. They sometimes employ mathematical proposi- 
tions very extensively, in deducing inferences from fun- 
damental principles. Yet they always differ essentially 
from Mathematics, in treating of material beings, and not 
of abstract quantity. They may be divided into the three 
following classes. (1) The inorganical, which treat of 
inorganic nature exclusively. (2) The organical, which 
treat only of organic nature, or of plants and animals. 
(3) The geographical, which treat of both. The first 
class comprises the mechanical, which treat of pondera- 
ble matter, and the ethereal, which treat of imponderable 
matter. Ponderable matter is that which gravitates, or 
possesses weight: imponderable matter is that which 
does not gravitate, or possesses no weight. 

1. The mechanical sciences treat chiefly of the me- 
chanical properties of matter, the forces dependent on 
these properties, and the motions or equilibrium which 
they produce. Mechanical properties are those which 
are directly cognizable by our senses, and at the same 
time tend to produce motion or rest in the bodies in 
which they inhere, such as weight, rigidity, elasticity, 
fluidity, roughness and smoothness. The following are 
the sciences belonging to this subdivision. 

(a.) Mechanic, which treats of solid bodies, or those 
whose parts firmly cohere. It consists of three parts — 
Static, which treats of solid bodies in a state of equilib- 
rium — Dynamic, which treats of the motions of such 
bodies, and the forces by which they are produced — and 
Mechanism, which treats of the mechanical properties 
of solids, the communication and distribution of motion, 
and the principles of machinery and engineering, irre- 
spectively of the moving forces. (19) 

(b.) Hydric, which treats of liquids, or those bodies 
whose parts do not cohere, or only very slightly, but yet 



Sec. 1.] Scientific Knowledge. 335 

are not repelled, and move with little mutual friction. 
It consists of Hydrostatic, which treats of liquids in a 
state of equilibrium — Hydro-dynamic, which treats of 
liquids in motion — PTydromechanism, which discusses 
the mechanical properties of liquids, the means of rais- 
ing, conducting and confining them, and the principles 
and construction of water works. 

(c.) Pneumatic, which treats of gaseous bodies, or 
those whose parts, instead of cohering, are mutually re- 
pelled from each other. 

(d.) Acoustic, the science of sound and hearing. As 
air is the ordinary medium of sound, this science is close- 
ly connected with the preceding. 

(e.) Astronomy, the science of the heavenly bodies. 
It is subdivided into Practical, which treats of the use 
of astronomical instruments, and the apparent magni- 
tudes, positions, aspects and motions of the heavenly 
bodies — Descriptive, which discusses their real condi- 
tions, motions, sizes, and distances — and Dynamical, 
which investigates the nature and effects of the forces 
that control their motions, and thence deduces their fu- 
ture positions, so that these can be accurately laid down 
in tables. Descriptive Astronomy is subdivided into 
Heliography, Selenography, Planetography, Cometogra- 
phy and Asterography or /Sidereal Astronomy, which 
treat respectively of the Sun, Moon, planets, comets, and 
fixed stars. 

2. The ethereal sciences treat of the properties of the 
imponderable agents, all of whose phenomena appear to 
depend on different kinds of undulations, or small waves, 
propagated through an invisible and very subtile medium 
termed ether, whence I have designated them as above. 
They consist of the following sciences. 

(a.) Optic, the science of light and vision. It is sub- 
divided into Physical, which treats of the nature of light 
and vision, — and Mathematical, which discusses the pro- 
duction of images, and the consequences deducible from 
the general laws of reflection, refraction and polarization. 

(b.) Thermotic, the science of heat. Like the preced- 
ing, it may be subdivided into the Physical and the 
Mathematical. 

(c.) Electric, the science of electricity. It may be sub- 
divided into — Electrostatic, which treats of electricity in 
equilibrium — Electrodynamic, which treats of electricity 



336 Classification of Knowledge. [Chap. XXL 

in motion — and Electromechanism, which investigates 
the nature and force of the electric fluid, and the pecul- 
iar principles of machinery worked by electric forces. 
Electrodynamic includes Galvanism, which treats of gal- 
vanic or ordinary electric currents, and Magnetism, which 
treats of magnetic electricity 

3. The organical sciences are the following . 

(a.) Botany, the science of plants, or inanimate organ- 
isms. It consists of Phytology, which treats of the struc- 
ture and development of plants in general — and Descrip- 
tive Botany, which describes the peculiar properties of 
the various subdivisions, classified according to their 
structure. 

(b.) Zoology, or Natural History, which describes the 
various kinds of animals. It consists of as many subdi- 
visions as there are classes of animals, such as Mammal- 
ogy (history of mammals) — Ornithology (history of 
birds) — Herpetology (history of reptiles) — Ichthyology 
(history of fishes) — Malacology (history of mollusks) — 
Entomology (history of insects) — Helminthology (his- 
tory of worms) &c. 

(c.) Anatomy, which describes methodically the vari- 
ous organs of animals, and the specific functions of each. 
It is subdivided into General, which treats of the organs 
of animals generally — Comparative, which discusses the 
analogous or corresponding parts of the various classes 
— and Human, which gives a description of all the organs 
of the human frame. 

(d.) Physiology, the science of the phenomena of ani- 
mated or living beings. Like Anatomy, it is subdivided 
into General, which discusses the structure and functions 
of animal organisms generally — Comparative, which 
treats of such as are peculiar to the various classes of 
animals — and Human which is confined to man alone, 
and includes Hygiene, the doctrine of the laws of health, 
and Ethnology, which investigates the origin and physic- 
al characteristics of the various races of men. 

(e.) Pathology, which treats of the phenomena and 
laws of morbific and curative agencies. It comprises 
Nosology, which treats of the general nature and phases 
and the classification of diseases — JEtiology, the doctriue 
of the causes of diseases, including Toxicology, which 
treats of the action of poisons — Symptomatology or Se- 
meiology, including Anatomical Pathology, which treats 






Sec. 1.] Scientific Knowledge. 337 

of the characteristic symptoms of diseases, and of the in- 
dications of their future course and results — and Thera- 
peutic, which discusses the remedies and proper treat- 
ment of diseases, including the nature, operations and re- 
sults of medicines and other curative agencies. These 
branches are properly blended with each other, in many 
instances; and they are all closely connected with the 
arts of Surgery and Medicine. 

4. The geographical sciences treat of the Earth, and 
such of its natural phenomena as do not belong to any 
of the preceding sciences. They consist of Geography, 
Chemistry, Mineralogy and Geology. 

(a.) Geography gives a general description of the 
Earth, and the scientific phenomena presented by its sev- 
eral parts, including a general account of their animal 
and vegetable productions. It may be subdivided into 
General or Mathematical, which treats of the form, size, 
motions and density of the Earth, and the means of de- 
termining the positions and distances of places on its 
surface, and delineating them on a sphere or plane — 
Geognosy, which' discusses the natural phenomena pre- 
sented by the land — Hydrology, which treats of the 
oceans, seas, and streams — and Meteorology, which gives 
an account of the general properties of the atmosphere 
and its phenomena, including aerial, aqueous, and lumin- 
ous meteors, and the extensive and interesting subjects 
of winds and climates. 

(b.) Chemistry investigates the nature of the simple 
substances of which all ponderable objects are com- 
posed, and describes both these elements and the com- 
pounds formed from them, including the laws of their 
composition and decomposition. It is subdivided into 
Inorganic, which treats of the simple elements, and such 
compounds as are found in inorganic substances — and 
Organic, which treats of such compounds as occur only 
in organic bodies. 

(c.) Geology treats of the rocks or mineral masses that 
compose the Earth, and of the organic remains contained 
in them. It may be subdivided into Petrology, which 
describes the various rocks, and investigates their origin 
— and Palaeontology, which describes the organic re- 
mains found in the rocks, and investigates the structure 
of the original organisms, and the circumstances in which 
they existed. 

P 



338 Classification of Ks-owlfdge. [Chap. XXI. 

(d.) Mineralogy discusses the chemical composition, 
the mechanical properties, the crystaline form, and the 
situation of solid minerals and crystals. It may be sub- 
divided into JJine renography, which treats of the chem- 
ical composition and other properties of minerals, apart 
from their crystaline form — and Cry holography, which 
treats of the crystaline form of minerals. 

HI. The mental sciences are those which chiefly regard 
mind, or things imperceptible to the senses, and treat of 
other matters only as connected with their main subjects. 
They are included in the following enumeration. 

1. Logic, which has been already defined. 

2. Psychology, the science of the human mind. It un- 
folds the nature of the mental faculties, both intellectual 
and emotional, and discusses everything regarding them 
which does not fall within the province of Logic. 

3. Theology treats of the existence and attributes of 
the Deity, and the relation in which man stands to him, 
as an intelligent and immortal being. It consists of 
Natural Theology, which investigates the evidence re- 
garding God and the future destination of man afforded 
by the works of nature — and Biblical Theology, which 
pursues the same subjects, under the additional light de- 
rived from the Sacred Scriptures. 

4. Morality or Ethic inquires into the nature and 
sanctions of duty in general, and investigates the princi- 
ples which determine particular duties. 

5. Jurisprudence is the science of juridical law. It 
consists of two parts — Public Jurisprudence, which in- 
vestigates the foundation and sanctions of government, 
and discusses the structure and peculiarities of its vari- 
ous leading forms — and Private Jurisprudence, which 
investigates the subjects and principles of private law. 
Each part may be subdivided into Xational and Interna- 
tional. National Public Jurisprudence treats of the in- 
ternal government of a nation. It exhibits the functions 
of the various departments of government, and the prop- 
er modes of conducting public affairs. Interna - 
Public Jurisprudence discusses the intercourse between 
different states, or between individuals and foreign _ 
eminent s. National Private Jurisprudence unfolds the 
juridical rights and duties of private members of a state, 
in relation to each other. I - I JM Juris- 
prudence shows the mutual rights and obligations of 



Sec. 1.] Mixed Knowledge. 339 

private subjects of different governments, in their inter- 
course with one another. 

The science of jurisprudence is to be distinguished 
from an exposition of the laws of a particular state, two 
things which differ as much as Hygiene and an account 
of the mode of living of some particular community. 
The former is as unchangeable as the nature of man : the 
latter changes from age to age, or even from year to 
year, so that it is not a science at all, but merely an art, 
to enable a man to expound or administer the existing 
laws of the state. 

§ 2. Mixed Knowledge. — What is meant by this term. — Subdivi- 
sions. — Art. — (1) Philology. — Dead and Living Languages. — (2) 
Ethnography. — Archeology. — (3) Technology. — Three principal 
kinds of Arts. — Distinctions. 

By mixed hnoioledge are understood those branches 
of which general propositions and particular statements 
form essential parts. It may be subdivided into Philol- 
ogy, which treats of words or language — Ethnography, 
which describes states, communities, and towns — and 
Technography, which discusses the modes of operating 
in the various arts. An art is, a body of rules for effect- 
ing some known end, with such directions and explana- 
tions as may be requisite for their due application. 

1. Philology may be divided into three main parts : 
(1) Special Philology or Grammar unfolds the elements 
and structure of some particular language, and lays down 
rules for obtaining an adequate knowledge and command 
of it. It consists of two parts — (a) that which treats of 
dead languages, or those which have ceased to be spoken 
by any community — and (b) that which treats of living 
languages, or such as are used by communities, as then* 
ordinary speech. (2) Comparative Philology treats of 
the agreements and diversities exhibited by one or more 
groups of kindred languages. (3) General Philology 
discusses the structure of language in general, and the 
conditions requisite in order to its fulfilling the objects 
of language. 

2. Ethnography comprises descriptions of the follow- 
ing subjects. (1) The political divisions and institutions 
of the various states, including the nature of their gov- 
ernments and laws. (2) Their races of men, populations, 
and resources. (3) Their religious tenets, and moral 



340 Classification of Knowledge. [Chap. XXL 

condition. (4) Their social institutions, manners, and 
customs. (5) Their language, science, and literature. 
(6) Their arts, manufactures, and commerce. (7) Their 
cities, towns, and remarkable edifices. (20) 

The condition of all these subjects generally varies, 
more or less, from age to age ; and the description may 
apply either to the present or the past, in which case it 
is frequently termed Archaeology or Antiquities. 

3. Technology comprises the three following classes 
of arts. 

(1) The mechanical, which aim at effecting some change 
in material elements, to minister to the necessities or the 
comfort and convenience of mankind, such as Tillage (in- 
cluding Agriculture, Horticulture, and Arboriculture), 
Pasturage, or the art of managing flocks and herds, Met- 
allurgy, Spinning, Weaving, and Architecture. 

(2) The intellectual, or those whose immediate object 
is, to solve problems, although some material change is 
often sought, as a further end. Such are Government, 
the art of executing the public laws — Statesmanship, 
the art of obviating difficulties in the administration of 
these laws, and improving them where bad or defective 
— Diplomacy, the art of conducting negotiations with 
foreign governments — Law, the art of expounding and 
administering the private laws — Rhetoric, the art of per- 
suasion and the communication of truth — Education, the 
art of training and instructing the young — and Naviga- 
tion, the art of directing the course and finding the posi- 
tion of a ship at sea. 

(3) The emotional, or such as are designed chiefly to 
excite agreeable feelings. Of this kind are Poetry, Mu- 
sic, and the imitative arts, including Painting, Photog- 
raphy, and Sculpture. They differ from Rhetoric in 
making pleasing feelings their chief end, whereas the for- 
mer uses these only as means towards its main object 
of producing conviction and action. They also differ 
from the sciences in making instruction and mental dis- 
cipline only secondary ends, while the sciences reverse 
the case, and make these their chief objects. 

§ 3. Particular Knowledge. — Its most important Subjects. — (1) 
History. — Its chief divisions. — (2) Chronology.— (3) Biography. — 
Its principal Divisions. 

Exclusive of those which relate to science or art, par- 



Sec. 4.] Particular Knowledge. 341 

ticular facts of general interest or importance, belong 
chiefly to History, Chronology, or Biography. 

1 . History is, a narrative or continuous account of past 
events, regarding communities or classes of mankind, in- 
cluding a view of their more immediate causes and ef- 
fects. It consists of a great variety of parts, according 
to the country, time, or subjects embraced. That of the 
same age and country comprises the following (1) Eccle- 
siastical, or that of religious affairs and morals. (2) That 
of science, literature, and language. (3) That of legisla- 
tion and law. (4) That of political and military transac- 
tions. (5) That of domestic life and manners. (6) That 
of the arts, manufactures, and commerce. 

2. Chronology is, an investigation and exposition of 
the dates of historical events, for the purpose of their 
being duly arranged in the order of their occurrence. 

3. Biography is, an account of the lives and characters 
of remarkable persons, the circumstances which directly 
influenced them, and the effects which they immediately 
produced. It bears much the same relation to individ- 
uals that History does to states or classes of men. It 
comprises the following divisions. (1) Religious and 
7noral, containing the lives of persons distinguished for 
their piety and benevolence. (2) Scientific and literary, 
including the lives of men of science, scholars, and au- 
thors. (3) Professional and Artistic, containing the lives 
of persons distinguished for great improvements or skill 
in the professions and arts. (4) Political and military, 
embracing the lives of celebrated rulers, statesmen, and 
warriors. (5) Miscellaneous, including the lives of per- 
sons distinguished in several respects, or for something 
peculiar or remarkable connected with them, exclusive 
of any personal excellence or achievement. These vari- 
ous parts may be subdivided according to time and place. 

§ 4. Table op the Principal Branches of Knowledge. 
I. The Sciences. 
1. Mathematics. 

{Arithmetic. 
., , Elementary. 
Algebra ^ TT . , 
& ( Higher. 

{Synthetical. 
. , . ■ f Determinate. 
y | Indeterminate. 



342 Classification of Knowledge. [Chap. XXI. 



2. The Physical Sciences. 
C 
(a.) Mechanic 



(1.) Mechanicals 



(6.) Hydric 



Static. 

Dynamic. 

Mechanism. 

i Hydrostatic. 
Hydrodynamic. 
Hydromechanism. 



(c.) Pneumatic. 
(d.) Acoustic. 

{Practical. 
Descriptive. 
Dynamical, 
(a.) Optic. 
(6.) Thermotic. 



(2.) Ethereal 



(c.) Electric 



(a.) Botany 



(6.) Zoology 



(8.) Organical < 



(4.) Geographical 



3. Mental Sciences. 
(1.) Logic. 



{Electrostatic. 
Electrodynamic, including 
Galvanism and Magnetism. 
Electromechanism. 
( Phytology. 
( Descriptive Botany. 
Mammalogy. 
Ornithology. 
Herpetology. 
Ichthyology. 
Malacology. 
Entomology. 
^Helminthology, &c. 

{General. 
Comparative. 
Human. 
( General. 

(A) Physiology I Human.tnduding 

( Hygiene and Ethnology. 

( Nosology. [cology. 

I JEtiology, including Toxi- 
(e.) Pathology < Symptomatology, including 

j Anatomical Pathology. 

I Therapeutic. 

( General. 
(«,) Geography Jjgg"* 

( Meteorology. 

w**» {?r„„foW. 



Sec. 4.] Table of Knowledge. 343 

(2.) Psychology. 

/-o \ rr.u i 1 Natural. 
(3.) Theology | BiblkaL 

(4.) Morality or Ethical Science. 

{( 1 P hi' i National. 
^ '•' I International. 

rt,' . t ('National. 
^•) Pnvate { International. 

II. Mixed Knowledge. 

1. Philology. 

(2.) Comparative. 
(3.) General. 

2. Ethnography. 

(1.) Political Divisions and Institutions. 

(2.) Races of Men, Population, and Resources. 

(3.) Religion and Morals. 

(4.) Social Institutions, Manners, and Customs. 

(5.) Language, Science, and Literature. 

(6.) Arts, Manufactures, and Commerce. 

(7.) Cities, Towns, and Remarkable Edifices. 

3. Technology. 

(1.) Mechanical Arts. 
(2.) Intellectual Arts. 
(3.) Emotional Arts. 

III. Particular Knowledge. 

1. History. 

(1.) Ecclesiastical. 

(2.) Scientific and Literary. 

(3.) Legal. 

(4.) Political and Military. 

(5.) Social. 

(6.) Artistic and Commercial. 

2. Chronology. 

3. Biography. 

(1.) Religious and Moral. 
(2.) Scientific and Literary. 
(30 Professional and Artistic. 
(4.) Political and Military. 
(5.) Miscellaneous. 



34i Mathematics. [Chap. XXIL 



CHAPTER XXII. 

OF MATHEMATICS. 

§ 1. PEcrxiAETTTEs of Mathematics. — General Nature and Sub- 
jects of Mathematics. — Errors regarding them. — Distinction be- 
tween a Theorem and a Problem. — Mathematical Definitions. — 
How the essential nature of Mathematical Quantities is known. — 
Axioms. — Mathematical Reasoning. — Characteristic of Analysis. 
— Its relation to Geometry. — General Principle which connects 
the two. — Unit of Measure. 

Mathematics adopt, as primary premises, the exist- 
ence and some self-evident properties of certain abstract 
quantities, the essential peculiarities of which are either 
accurately defined or known by Intuition ; and they de- 
duce from these premises, by means of ordinary reason- 
ing, and independently of experience, a long series of 
connected inferences and conclusions, which express the 
properties and relations of those quantities, and consti- 
tute the body of these sciences. Hence Mathematics are 
based, in no degree, on experience or testimony, and they 
are totally independent of every other department of 
knowledge, while their truths are all necessary, and never 
contingent, so that they are universally true, independ- 
ently of time and place. 

Some have considered mathematical truths only hypo- 
thetical, upon the alleged ground that mathematical quan- 
tities do not exist in nature. But the existence of such 
quantities is as self-evident as that of time and space. 
Although the most slender wire has some breadth, yet, 
there is a mathematical line ru>nuing through it which 
has none. Such quantities not only exist, but they are 
wholly independent of the physical objects which may 
have suggested to us their nature, or in connection with 
which we frequently consider them. 

Another error regarding Mathematics is, that they are 
based chiefly on observation. It is easily seen that they 
are quite independent of observation, which shows only 
what is, at a particular time and place, while these sci- 
ences are confined to propositions which are necessarily 
true, in all times an$ places. 



Sec. 1.] Their Peculiarities. 345 

The distinction betAveen a theorem, or something laid 
down to be proved, and a problem, or something proposed 
to be done, is not fundamental, but only formal, since the 
thing to be done is effected by means of some theorem, 
which is proved, though not formally stated. The prob- 
lems are, in fact, corollaries, or easy inferences from the 
theorems ; and every problem might be stated as a the- 
orem, and the mode of forming the figure, or calculating 
the quantity, appended as a corollary. 

Mathematical definitions are generally suggested by 
obvious properties of material objects with which we are 
familiar : but we abstract from the definition something 
which is present in the object ; and we frame it so that 
we can reason from it w T ith rigid accuracy, irrespectively 
either of the additional peculiarities or the variations 
found in physical objects. Such definitions are not only 
very precise and intelligible, but they give us a knowl- 
edge of the essential peculiarity of the thing defined. 

The essential nature of the thing defined is known in- 
tuitively, by simply considering the definition, although 
physical symbols facilitate an understanding of the defi- 
nition. Indeed, in various instances, we know the nature 
of the quantity without any definition. Thus we know 
the nature of a straight line and a plane rectilineal angle, 
as soon as we see two straight lines crossing each other, 
while all the definitions of them that can be given are 
only verbal, and help us to understand the nature of the 
quantities as little as definitions of red or blue. 

Mathematical reasoning does not differ from any other 
reasoning. The intuitive principles employed are termed 
axioms: but they differ, in no respect, from other prin- 
ciples of reasoning, and they are employed in the same 
way. Several of them, indeed, are formally stated ; but 
this makes no difference in the reasoning, which is inde- 
pendent of any such statements. Not only are these not 
made, in many treatises on Mathematics ; but those which 
do give them, employ many which they do not state or 
formally refer to. 

The characteristic of Analysis is, that it immediately 
regards number only ; and it indicates magnitudes solely 
because these are expressible by numbers. The processes 
employed in Analytical Geometry are not more applica- 
ble to Geometry than to other subjects that fulfil the same 
numerical conditions. Geometrical properties are ascer- 
P2 



346 Mathematics. [Chap. XXII. 

tained by means of Analysis, because they bear certain 
obvious or ascertainable relations to the numbers express- 
ing the magnitudes of the various parts of its figures. 
Synthesis is connected with Analysis by the general prin- 
ciple that the properties and relations of magnitudes cor- 
respond to those of the symbols which rightly represent 
them. Thus, if one line is three inches long, and another 
five, the lines are to each other in that ratio. 

The letters employed in Analysis do not properly rep- 
resent quantity, but only the numbers that are assumed 
to measure them. A unit of measure is always assumed, 
in Analytical Geometry : otherwise Algebra would be as 
useless as it is in ordinary arithmetical calculation. But 
no unit need be expressed, because the results are unaf- 
fected by the particular one which is supposed to be em- 
ployed. 

§ 2. Uses of Mathematics. — (1) They form an excellent Mental 
Discipline. — (2) They are extensively employed, in many Arts and 
Sciences. — Applications of the various Parts. 

1. Mathematics are an excellent means of initiating the 
mind into habits of close and continuous reasoning. The 
study is comparatively easy ; and it is, in a great meas- 
ure, free from the prejudices and illusions which accom- 
pany several other branches of knowledge, while these 
sciences abound with long and rigorous chains of reason- 
ing, which must be attentively examined, before any real 
progress can be made in the study. 

2. These sciences are of great utility on account of 
their numerous applications in the arts and sciences, 
many of which are wholly dependent on them : and their 
assistance is more or less requisite, in order to obtain an 
extensive and accurate knowledge of most of the phys- 
ical sciences. Their applications in the arts are so fre- 
quent and familiar that it can hardly escape the knowl- 
edge of anybody ; and, even in History, the dates of many 
occurrences have been settled, and some anachronisms 
detected, by means of these sciences, where the problems 
could be solved in no other way. 

Ordinary numerical problems can be solved by means 
of Arithmetic : but those Avhich require us to operate 
with a quantity, before its value is determined, or to ex- 
press general properties, can be solved only by means of 
the concise and general symbols of Algebra. For we 



Sec. 3.] Study of Mathematics. 347 

cannot, by any other means, either remember the various 
parts of the process, so as to perform the requisite oper- 
ations aright, or discuss satisfactorily the relations of the 
several quantities. 

All problems relating to magnitudes require the aid 
of Geometry, although that of Analysis also is generally 
more or less requisite. (21) N 

§ 3. Study op Mathematics. — Most important Points, at the Com- 
mencement. — Principal things to be guarded against. — Superior 
Methods. — Aids of Generalization. — Selection of Propositions. — 
Working Problems. — Positive and Negative Results. — Signification 
of isolated Negative Quantities. — Source of Difficulty. — Extended 
Significations. — Distinction. — Imaginary Quantities. — Advantages 
of Analytical Geometry. — Uses of the Synthetical. — Means of ex- 
tending and improving Mathematics. — Effects of the exclusive 
Study of Mathematics. — How obviated. 

The most important point, in commencing the study 
of any branch of Mathematics, is, to obtain precise and 
accurate views of the fundamental principles and the im- 
port of the symbols, in order to which the nature of the 
things must be considered, apart from the definitions. 

The principal defects against which the student should 
be on his guard, are, vague or inaccurate definitions and 
sophistical reasoning. Although mathematical demon- 
strations profess to establish the conclusions beyond the 
possibility of any doubt or uncertainty, yet they some- 
times fail to do so, more especially in the higher depart- 
ments, in which they occasionally establish only a prob- 
ability. Consequently the student should ascertain how 
far the demonstration extends, and distinguish what is 
proved from what is not. 

Wherever there is a choice, the learner should prefer 
the most general methods, as they are the most compre- 
hensive and powerful. This will both save time, and en- 
able him to master difficulties which are not easily sur- 
mounted without such aids. He should, therefore, ob- 
tain a good knowledge of the Higher Analysis, which 
presents no serious peculiar difficulty, and which is very 
superior to the comparatively feeble and prolix methods 
of the older mathematicians. (22) 

Attention to the symmetry and regularity of expres- 
sions is an important means of discovering the more gen- 
eral laws : and it may be said with truth that a proper 
series of symbols, and a due arrangement of terms, are 



348 Mathematics. [Chap. XXII. 

equally advantageous to the student and the original in- 
vestigator. 

Those propositions which are either necessary links in 
the chain of demonstration, or valuable for their applica- 
tions, are amply sufficient for the purposes both of men- 
tal discipline and practice; and the student should be- 
ware of spending much time on the endless list of curi- 
ous problems of no application. Indeed particular prob- 
lems and examples should occupy little time, and be em- 
ployed merely as elucidating theorems, which is general- 
ly their only real use. The practical problems which oc- 
cur in the sciences and arts based on Mathematics form 
the best exercise, either for mental discipline or the at- 
tainment of readiness and skill in calculation. Working 
problems mechanically, by rules whose real character is 
not known, stultifies the mind almost as much as repeat- 
ing by rote demonstrations which are not understood. 

In Arithmetic, every expression and result is viewed 
as positive : but, in Algebra, the case is frequently oth- 
erwise, because the precise nature of the problems or of 
the quantities sought may not be clearly understood at 
the outset, or the problem admits of several symmetrical 
solutions. 

We can always understand the precise signification of 
an isolated negative quantity, such as — a, by remember- 
ing the self-evident truth that +a—a (or a— a) = 0: 
and, therefore, if we know what a or -f- a signifies, we 
need have no difficulty in understanding what — a means : 
for we must interpret it so that, when we prefix -+-«, we 
are brought to 0, zero, or the starting point, which is 
well known, and through which we pass, in going from 
+ to — or the reverse. 

The learner is apt to be puzzled by assuming that — a 
denotes a quantity less than nothing, whereas it denotes 
the same amount as +«, but taken reversely. Thus, if 
-\-a mean such a distance from a cei'tain line measured 
to the right, —a means that distance measured from the 
same line to the left : if the former mean so much meas- 
ured upward, the latter means so much measured doicn- 
ward, and so on. 

In Algebra -j- often means simply that the quantity to 
which it is prefixed is measured in a certain direction, 
and — , that it is measured in a contrary direction. The 
former sign is prefixed to the quantities which are deem- 



Sec. 3.] Study of Mathematics. 349 

ed additive, positive or increasing, being those which 
were first considered ; and the latter is prefixed to those 
which are deemed subtractive, negative or decreasing, 
being those which come into view in examining the less 
obvious aspects of the proposition. But, so far is this 
from indicating absolute addition or subtraction, that the 
signs might frequently change places, without any incon- 
venience. Thus, in Analytical Geometry, distances to 
the right of the vertical co-ordinate are indicated by -|-, 
and those to the left by — , evidently because we write 
and read towards the right: but had the science orig- 
inated with those Asiatics who write and read the other 
way, they would probably have reversed this use of the 
signs; and this would be naturally as proper as our 
method. 

The student must not confound abstract with concrete 
numbers, nor attempt to apply to the former what prop- 
erly belongs only to the latter. All abstract numbers 
are essentially positive : and, therefore, to speak of multi- 
plying one abstract number —a by another absti'act num- 
ber —b, is, to heap one absurdity upon another, because 
abstract numbers less than nothing cannot exist. But 
when we come to concrete numbers, or those which de- 
note quantities measured in a certain way, or particular 
kinds of quantity, the case is greatly altered ; and we 
must then apply the properties of abstract numbers only 
so far as they hold good. 

In dealing with concrete numbers, we are not bound 
to stop at the zero or starting point, because quantity 
exists equally on both sides of it ; and we may proceed 
on one side as well as the other, only indicating on which 
side the quantities lie, by prefixing -f to the one, and — 
to the other. In abstract numbers, on the other hand, 
Ave cannot pass zero : for, when we reach that, our quan- 
tities wholly vanish. Concrete numbers are employed 
upon certain assumptions made at the outset, the nature 
of which must be mai'ked and attended to, if we would 
avoid confusion and error, whereas no such assumptions 
can be legitimately made in regard to abstract numbers. 
In order to render demonstrations and processes relating 
to concrete numbers perspicuous and valid, they must 
conform to the restrictions imposed by the particular as- 
sumptions made. 

Even those expressions which might appear to defy 



350 Mathematics. [Chap. XXII. 

every attempt to assign them a clear and definite signifi- 
cation, become quite intelligible, when their origin and 
nature are clearly understood. Such are, the square roots 
of negative quantities, which are termed imaginary or 
impossible, and which may all be reduced to the form 
a-\/ — 1. These arise from some inconsistency or impos- 
sibility, involved in the problem whence they originate ; 
and the result shows the nature of the absurdity, and 
how the problem must be modified, in order to remove it. 
A consideration of the origin and real import of such ex- 
pressions shows that they may be employed in opera- 
tions like others, that they are to be interpreted accord- 
ing to the nature of the problem in which they occur, 
and that, when they disappear from an equation, the re- 
sult is not, in the least, vitiated by their having entered 
into the operation. 

Analytical Geometry possesses over the Synthetical 
the advantages of greater generality and conciseness, and 
of furnishing means of testing hypotheses and evolving 
consequences with much greater facility. Hence it is 
usually preferable even in those cases where the synthet- 
ical is applicable, while, in many cases, the latter is quite 
useless. Yet it furnishes the only means of establishing 
the principal propositions of Elementary Geometry; and 
it affords more concise and elegant demonstrations of 
particular propositions than the other. 

As Mathematics are independent of observation, ex- 
periment, or testimony, they can be extended and im- 
proved chiefly by means of indirect discovery and inven- 
tion, the only exception being, where a discovery is made 
accidentally, while performing a process. The higher de- 
partments admit of indefinite extension : yet, as the field 
is already very wide, it is desirable that what is known 
should be generalized, abridged and elucidated, before 
we are required to proceed much farther. It sometimes 
happens, however, that new discoveries totally supersede 
more tedious and feeble methods previously in use : and 
we cannot have too many discoveries of that kind ; for 
they abbreviate the sciences, while they render them 
more powerful in their application. Testing hypotheses 
analytically forms one of the principal instruments of 
progress in this direction. 

The exclusive study of Mathematics naturally tends to 
produce credulity, scepticism, one-sided views, and a hab- 



Sec. 1.] Physical Sciences. 351 

'it of regarding mere expressions, without paying suffi- 
cient attention to what they denote. Moreover, as Math- 
ematics exercise no influence on the feelings or morals, 
those who study nothing else are, so far as these are con- 
cerned, on a level with those who study nothing. But 
such tendencies are completely obviated by studying the 
organical and mental sciences. The mechanical and ethe- 
real sciences hardly furnish a sufficient antidote, on ac- 
count of their close resemblance to Mathematics. 



CHAPTER XXIII. 

OF THE PHYSICAL SCIENCES. 

§ 1. Of the Physical Sciences in general. — Differences between 
Physics and Mathematics. — Of what the former consist, and on 
what based. — Directions for Study. — General Uses of Physics. 

This class of sciences differs essentially from Mathe- 
matics in being based on physical realities, instead of ab- 
stract quantities and definitions. Their fundamental 
principles are learned chiefly from experience and testi- 
mony ; and consequently they extend only to the present 
system of nature, and their truths, although general, are 
only contingent, without possessing, to any great extent, 
the universality of Mathematics. They consist mostly 
of inductions regarding material objects, and inferences 
from these inductions. Observations or experiments are 
generally required to establish the primary inductions ; 
and in many cases, these require to be numerous, and 
made with much care and skill. 

In studying these sciences, we should test the proofs 
on which the professed primary inductions rest, as some 
of those stated in several books are false. Besides guard- 
ing against vague and erroneous definitions and sophist- 
ical reasoning, as in Mathematics, the student must fur- 
ther beware of undue assumptions and fallacies of testi- 
mony. The definitions also require a more careful consid- 
eration than in Mathematics, as they may fail to express 
the essential peculiarities of the things defined, or to con- 
vey a correct and adequate notion of them, because they 
are much more complex and difficult to understand than 
mathematical quantities. ^ 



352 Physical Sciences. [Chap. XXIII. 

The physical sciences give us accurate, although inad- 
equate, views of nature and its Eternal Ruler. Hence a 
knowledge of them tends to banish superstition, and to 
strengthen the foundations of true religion. They also 
improve the faculty of observation, and teach us to look 
carefully to our premises, as well as to our inferences, so 
that they supply the most striking defect of Mathemat- 
ics, as an instrument of intellectual discipline. They also 
furnish many truths which are employed in the mental 
sciences, while their applications in the arts are innumer- 
able. 

§ 2. Op the Mechanical Sciences. — How these are to be studied. 
— (1) Mechanic. — Friction, and Strength of Materials. — (2) Hy- 
dric. — Inaccurate Definition. — Cohesion and Friction of Liquids. 
— (3) Pneumatic. — (4) Acoustic. — (5) Astronomy. — Means of as- 
certaining its Conclusions. — Difficulties. — Law of Gravitation. — 
Distinction. — Tables. — Eclipses. — Masses. 

This class resembles Mathematics so much that most 
of what was said regarding these, is equally applicable 
here. But there is occasion for more attention to the 
fundamental principles, which are much more liable to 
be fallacious than those of Mathematics, while there is 
less danger of our time being thrown away on futile in- 
vestigations. Yet it is possible to miss the most inter- 
esting and important parts of the subject, by dwelling 
too long on others. There are various curious problems 
in Mechanic, for example, that might not unjustly be 
classed with the magic squares and Diophantine Analy- 
sis of the old mathematicians, and Avhich it would be very 
improper to study, to the exclusion of Astronomy. 

1. Mechanic is based partly on intuitions, and partly on 
simple observation and experiment, but more on the last 
than on the second. The force of terrestrial gravity is 
accurately determined by means of Atwood's falling ma- 
chine ; the velocity of projectiles can be approximately 
measured by the ballistic pendulum; and the laws of 
equilibrium are established or confirmed by numerous 
experiments with weights, levers, pulleys, screws, inclined 
planes, &c.(23) 

Most of the manual arts are, more or less, dependent 
on Mechanic, which also forms the chief foundation of 
the other mechanical sciences, and is of frequent applica- 
tion in the organical and geographical sciences. 

A very important part of this science is, that which 



Sec. 2.] Mechanical Sciences. 353 

treats of friction and the strength of materials, things 
which can be properly determined only by numerous 
careful experiments. Many lives have been lost, and 
much property has been destroyed, owing to ignorance 
or erroneous views of these subjects. 

2. Hydric adopts the conclusions of the preceding sci- 
ence, and derives its other primary premises chiefly from 
observation and experiment. The specific gravity of liq- 
uids can be accurately ascertained by means of the hy- 
drometer ; the laws of their motions are deduced from 
observations on streams, and experiments with tubes, ar- 
tificial canals, and vessels from which water is made to 
issue through an orifice. Reasoning, apart from experi- 
ence, is of comparatively little avail in this science : yet, 
by combining the results of experiments and mathemat- 
ical principles, much may be learned that is of great use 
in the construction of pumps, fire-engines, and water- 
works, including canals, and also in determining the best 
forms of ships and their moving apparatus, as well as the 
best methods of loading and working them. 

A liquid has been frequently defined " a substance which 
communicates pressure equally in every direction." But 
this definition is inaccurate : for it is applicable only to a 
fluid whose particles are totally destitute of cohesion, 
which is not the case with any known liquid, nor espe- 
cially with water, the principal liquid of which we have 
any knowledge. The drops pendent from the fingers, 
after being dipped in it, prove that its particles cohere ; 
and as these are larger as the water becomes colder and 
denser, it appears that the force of cohesion varies with 
the temperature. 

The fact that all liquids possess friction, has been some- 
times overlooked, although this property exerts an ex- 
tensive influence on their motions. Owing to this, and 
the preceding erroneous definition, the actual motions of 
liquids are widely different from what the theories of 
several writers on this subject indicate: and the influence 
of cohesion and friction must be accurately ascertained 
before Hydric can approach perfection. 

3. The principles of Pneumatic are based on Hydric, 
and experiments made with the thermometer, barometer, 
condenser, pressure-gauge, and eudiometer. It consists 
mostly of primary facts, and contains few long chains of 
reasoning. The subject of cohesion cannot cause any 



354 Physical Sciences. [Chap. XXTTT . 

difficulty here, as the particles of all gaseous bodies or 
aeriform fluids are strongly repelled : but this renders 
the influence of friction very extensive; and the extreme 
rapidity "with which their density changes, with slight 
variations of temperature, increases the difficulty of de- 
termining their movements, otherwise than by direct ob- 
servation or experiment. 

The great importance of air, as a prime necessary of 
life, and its extensive agency in many of the most inter- 
esting phenomena of physical nature, render this science 
as important as it is beautiful. To it chiefly belong the 
properties of steam, and the principles of the steam-en- 
gine. 

4. Acoustic is based chiefly on Pneumatic, the well- 
known phenomena of hearing, and experiments made on 
sonorous substances and the transmission of sounds 
through various bodies. It is less extensive than the 
preceding science : yet the importance of hearing, the 
singular phenomena of vibrating strings and surfaces, 
and its applications to determine the proper forms and 
arrangement of rooms for public speaking, render it both 
interesting and curious. It also derives an extraneous 
importance from the light which it throws on the ether- 
eal sciences. To it also belong the theory of Music and 
the vibrations of sounding bodies, which reveal several 
remarkable peculiarities of solid bodies, not discoverable 
otherwise. 

5. The immensity and grandeur of its subjects vindi- 
cate for Astronomy the conspicuous place which it has 
always held among the physical sciences : for it treats, 
not only of worlds, but of countless systems of worlds, 
at distances of which we can form no adequate concep- 
tion. The astounding magnitude of the Sun, the all-dis- 
solving heat and intolerable glare of light on its surface, 
its huge swift-rolling waves of fluid fire, and its vast ever- 
varying Tartarean shades, form most sublime subjects of 
contemplation. Nor is this science devoid of practical 
applications. Without its aid, it is impossible to navi- 
gate the ocean in safety, to ascertain the positions of 
places on the Earth, to d'etermine the hour of the day, or 
the proper time for cultivating the fields, or even to ob- 
tain a permanent standard of weights and measures. 

This extensive science is based on numerous observa- 
tions, made with instruments constructed with great- 



Sec. 2.] Astronomy. 355 

est attainable accuracy, and used with the utmost care, 
skill and dexterity. Inferences are then drawn from the 
observations, by means of Mathematics, Dynamic and 
Optic, a competent knowledge of which is indispensable 
to the successful study of the heavens. 

By means of a transit instrument, and a clock which 
shows sidereal or star time, the astronomer finds the me- 
ridian altitude and time of culmination of such bodies as 
occupy the same apparent places for any considerable 
period ; and this determines then* apparent positions on 
the celestial sphere. The altitude and azimuth instru- 
ment, or an equatorial, enables him to ascertain the ap- 
parent position of an object which is not on the meridian. 

The telescopes and micrometers which form a part of 
those instruments, enable the observer to measure very 
accurately the apparent size of such bodies as exhibit any 
disc or visible surface, and also to ascertain their appear- 
ances. By observing from day to day, or from hour to 
hour, the places of those objects which change their rela- 
tive positions, their apparent paths, as well as their vary- 
ing phases, are exactly determined, whence their real 
motions are ascertained by forming hypotheses, and test- 
ing them by the proper criterions. It is thus found that 
the phenomena accord only with the supposition that 
the planets, including the Earth, have a diurnal motion 
on their axes, and another around the Sun, while the sat- 
ellites revolve round their respective primaries — that the 
Sun also revolves on its axis and slowly round a very 
distant center — and that many, if not all, the fixed stars 
have a similar motion in space, although they are too re- 
mote to ascertain whether they have any diurnal motion. 

The distances of the heavenly bodies maybe ascertain- 
ed by measuring the differences in their apparent posi- 
tions when viewed from two points of the Earth's sur- 
face or orbit, whose distances from each other are known, 
the mean radius of the Earth or of its orbit being adopt- 
ed as the unit of measure. The process is the same as 
that by which we ascertain the distance of a terrestrial 
object, when we take the angles which it forms with a 
line of known length, measured from the two extremities 
of the line. In each case, we have a side and the three 
angles of a triangle, to find the other sides, which is very 
easily done, from the well-known theorem that the sides 
are proportional to the sines of the opposite angles. The 



356 Physical Sciences. [Chap. XXIII. 

only difficulty lies in making the measurements with suf- 
ficient accuracy. 

When once we know the Earth's distance from the Sun, 
that of any other planet from the Sun is readily ascer- 
tained from the law that the squares of the times of their 
revolutions round the Sun, are proportional to the cubes 
of their mean distances, a law which is a necessary con- 
sequence of those of motion and gravitation. 

The distance and apparent or angular magnitude of a 
heavenly body being known, it requires only the solution 
of the simplest problem in Trigonometry to determine 
its real diameter : for Radius is to the sine of half the an- 
gle of apparent magnitude, as the distance is to the semi- 
diameter. But this method is inapplicable to the fixed 
stars, because they show no discs ; and their magnitudes 
can only be conjectured from comparing the amount of 
light which they give with that which the Sun would 
impart at the same distance, the brilliancy of a body va- 
rying inversely as the square of its distance. 

Even this loose method fails in the case of most of the 
fixed stars, because they are so remote that their dis- 
tances cannot be ascertained even approximately, as the 
diameter of the Earth's orbit bears no measurable pro- 
portion to their distances. It is also to be observed that 
no astronomical quantity admits of being measured with 
as much accuracy as terrestrial magnitudes : a close ap- 
proximation is all that can generally be attained ; and, 
not unfrequently, we can obtain only a loose approxima- 
tion, as in the case of the distances of fixed stars. 

After ascertaining the distances, magnitudes, and real 
motions, of the members of the solar system, the laws of 
the forces that control these motions are ascertained by 
comparing them with those which determine the motions 
of a common projectile, and employing the ordinary laws 
of motion, and the principles of Mathematics, in deducing 
the consequences necessarily implied in the phenomena. 
This process was first applied to the Moon, then extend- 
ed to the Earth's motions around the Sun, and after- 
wards to the other planets. 

Thus was established the law of gravitation, which ac- 
counts for all the motions of those bodies, and enables 
the astronomer to determine the perturbations of the 
planets, or the irregularities in their movements caused 
by their mutual influence on each other, so that their fa- 



Sec. 2.] Astronomy. 357 

ture positions can be accurately ascertained, and laid 
down in tables. It is observable, however, that the law 
only expresses the fact of the existence of a certain force, 
and the modes in which its influence varies : it gives no 
explanation whatever of the origin or real nature of the 
force. 

When once accurate tables have been constructed, the 
future places and phases of the bodies can be found with 
comparatively little labor, as we are furnished with all 
the principal elements of the calculation, ready for use. 
Thus, if we wish to ascertain the number and character- 
istics of the eclipses that will occur next year, we first 
ascertain the positions of the Sun and Moon at its com- 
mencement. Then from the motions of these bodies in 
their orbits, as given by the tables, we ascertain how oft- 
en the Moon will pass through the Earth's shadow, and 
the Moon's shadow strike the Earth, till the end of the 
year. The former will be the number of lunar, and the 
latter, of solar, eclipses. 

The ordinary rules of Trigonometry enable us to de- 
termine the times and peculiarities of the various eclipses, 
from knowing the relative positions of the Earth and the 
Moon, when the phenomena occur. Those peculiarities 
depend on the distances of the Earth from the Sun and 
Moon, and the latter's position in its orbit. Thus, in cal- 
culating a solar eclipse, the size of the Moon's shadow, 
at the Earth's distance, is wholly determined by their re- 
spective distances from the Sun ; and the particular parts 
of the Earth which the shadow will cross, can be ascer- 
tained from the position of the Moon's node, at the time 
of conjunction, while the duration of the eclipse is read- 
ily found from knowing the velocity of the Moon in its 
orbit. 

Knowing the Earth's distance from the Sun and Moon, 
and the latter's course and velocity in its orbit, the laws 
of motion and gravitation enable us to determine the pro- 
portion which the Earth's mass or weight bears to the 
Sun's, the latter being adopted as the unit of measure. 
The problem may be otherwise solved by comparing the 
influence of the Earth on a falling body with that of the 
Sun on the Earth. In the case of those planets which 
are accompanied by satellites, their masses are ascertain- 
ed by comparing their influence on these with that of the 
Sun. either on themselves or on their satellites. The 



358 Physical Sciences. [Chap. XXIII. 

masses of those planets which have no satellite, are ascer- 
tained approximately, by observing the perturbing influ- 
ence which they produce on some other body, whether 
planet or comet. The masses of the satellites are ascer- 
tained from the perturbations in their motions produced 
either by the Sun or by each other. That of the Moon 
may be farther ascertained from its effects in changing 
the Earth's axis, and its comparative influence on the 
tides.(24) 

§ 3. Of the Ethereal Sciences. — General Character of these Sci- 
ences. — Their special Use as a Study. — (1) Optic. — Origin and 
probable nature of Light. — (2) Thermotic. — Ultimate Source of 
Heat. — (3) Electric. — Origin of Electricity. — Electrostatic. — Gal- 
vanism. — Magnetism. — Electromechanism. — Probable Nature of 
Heat and Electricity. — Connection of these Sciences. 

These sciences resemble the mechanical in deducing 
numerous inferences from the primary facts, by means of 
Mathematics : but they differ from those, as well as from 
all the other physical sciences, in their subjects being of 
a more subtile nature, and less apprehensible by our 
senses. Consequently they are based much more on ex- 
periment than on simple observation ; and great care is 
requisite in establishing the primary inductions. Owing 
to their resemblance and close connection, they exten- 
sively aid and illustrate each other : and the true source 
and nature of their phenomena require to be understood, 
in order to surmount some of the difficulties which they 
present to the investigator. 

The study of these sciences is an important means of 
enabling us to form accurate views of nature ; and a 
knowledge of them is indispensable to right conceptions 
of the general structure and laws of the material crea- 
tion. An exclusive attention to the mathematical and 
mechanical sciences tends to make us estimate every- 
thing by its mass, firmness or momentum. But a knowl- 
edge of the ethereal sciences reveals to us that the forces 
which immediately control nature reside in those things 
which are least perceptible to our senses, and apparently 
the most feeble and inefficacious. We are thus led to 
understand how invisible and impalpable mind is the 
ultimate source of all powei\ 

1. A knowledge of Optic is requisite in order to the 
proper construction of optical instruments, while it is an 



Sec. 3.] Ethereal Sciences. 359 

important means of enabling us to preserve or improve 
the sight. The wide range of vision, and its necessity to 
our very existence, consequently render this science of 
the utmost importance, while the properties of light and 
color are such as to render it one of the most beautiful 
and interesting of all the physical sciences. Moreover, 
by transmitting polarized light through transparent bod- 
ies, we can ascertain peculiarities in their structure which 
can be discovered by no other means. 

The composition of white light is ascertained by sim- 
ply passing it through a common glass prism ; and other 
fundamental principles are established with the aid of 
reflecting, refracting, polarizing, and discolorable sub- 
stances, of various forms and kinds. The intensity or 
amount of light is measured approximately, by means of 
a photometer ; and its velocity is ascertained both from 
astronomical phenomena and from direct experiment. 

Light appears to consist of undulations, or small waves, 
generated by a rapid, vibratory motion of the luminous 
body's atoms, and propagated through ether, in every di- 
rection. The theory that it consists of solid, unconnect- 
ed particles, which fly from the luminous center, is at- 
tended with various insuperable difficulties. 

Not only do the rays "of light sometimes interfere, so 
as to destroy each other, but it is impossible that the 
Sun, for example, could have been throwing off such par- 
ticles, for any length of time, without being dissipated 
through the boundless void. It is no answer to this ob- 
jection to say that the particles are extremely small : for 
they must possess some bulk ; and the smaller their size, 
the greater must be their number, since they exist simul- 
taneously, at every point. Nor could such rays move in 
every direction, through every point, without interfering 
with each other to a much greater extent than they real- 
ly do. 

It is also impossible that the solar rays could fill every 
point, as they receded from the Sun, owing to the rapidly 
increasing surfaces of the spheres traversed, unless we 
adopt the absurd hypothesis that they regularly divided 
and subdivided as they advanced. Nor could such par- 
ticles permeate a great thickness of a hard and dense sub- 
stance, like glass, as light actually does. It is also in- 
credible that a black substance should receive an indefi- 
nite number of such particles, without furnishing the 



360 Physical Sciences. [Chap. XXIII. 

least indication that any such thing ever penetrated it, 
either by an increase of weight or otherwise. Moreover 
the tremendous momentum of such bodies, moving with 
a velocity of nearly two hundred thousand miles in a sec- 
ond, would have destroyed our sight, at the very first 
impulse. 

With regard to what are termed the chemical, or dis- 
coloring rays of solar light, I am aware that some consider 
them totally different from luminous rays : but there are 
some indications that they are only luminous rays, too 
small to affect our vision, under ordinary circumstances. 

2. Thermotic is a most important science, on account 
of the controlling influence of heat throughout the or- 
ganic creation. The changes of the seasons strikingly 
exhibit this influence on vegetation ; and it is equally 
extensive, though perhaps less obvious, in relation to liv- 
ing beings. Thus, if the temperature of warm-blooded 
animals is reduced a little below the natural standard, 
they speedily die, and a like result follows when their 
tempei'ature is raised a little above the normal heat. A 
variation from the proper temperature of the different 
parts of the body is also a fruitful cause of disease and 
death. The extensive applications of heat in the arts 
also invest the subject of its production with great inter- 
est, and render a knowledge of its sources and laws of 
great importance. 

The most interesting questions in this science are, 
those which regard the origin, distribution, and influence 
of heat. Its immediate sources are various : but they 
all seem to be ultimately referable, like light, to a vibra- 
tory motion of the atoms of the body whence it pro- 
ceeds. This may be produced by chemical or electric 
action, and by friction, or sudden and violent compres- 
sion. Heat always tends to dissipate rapidly through 
space ; and the circumstances which accelerate or retard 
its escape deserve a careful consideration. Myriads have 
lost their lives owing to their ignorance on this subject. 

Several of the laws of heat are learned by simple ob- 
servation ; and others are ascertained by means of the 
thermometer, pyrometer, calorimeter, and various reflect- 
ing, refracting, radiating, conducting, convecting and pol- 
arizing substances. 

3. The origin of electricity appears to be referable to 
the same ultimate cause as that of heat. It is generally 



Sec. 3.] Ethereal Sciences. 361 

produced by friction or chemical action : but it is equal- 
ly caused by heat. Its laws are mostly established by 
means of experiments, in which a great variety of instru- 
ments is used, including the common electric machine, 
the galvanic battery, the electroscope, electrometer, elec- 
trophorus, condenser, proof plane, and galvanometer, the 
magnet, and electromagnetic apparatus, of various kinds. 

Electrostatic claims attention on account of the pow- 
erful agency of statical electricity, both in nature and in 
the arts. A knowledge of it may be said to have divest- 
ed lightning of its terrors, and, from being a direful ene- 
my, converted it into a useful servant. It not only ex- 
plains the origin of lightning and thunder, but points out 
the mode in which we may guard against danger from 
the former, and how statical electricity may be usefully 
employed in the arts. 

Electrogalvanism, whose phenomena are produced by 
continuous currents of electricity, is of much importance 
on account of its extensive application, both in the arts 
and in many scientific experiments. In chemical analy- 
sis, for example, it affords one of the most powerful means 
of decomposing substances. It also furnishes the means 
of accurately measuring very small portions of time, and 
determining the precise instant of an occurrence, by 
means of the chronoscope and the electric clock, with 
their proper appendages. 

The phenomena of Electromagnetism arise wholly from 
electric currents : and terrestrial magnetism appears to 
consist of currents caused by the varying action of the 
Sun, during the diurnal revolution, whence its phenome- 
na exhibit the same changes which mark the weather 
and the seasons. 

The value of the magnet in Navigation renders this 
branch of Electric one of great importance, while it de- 
rives additional interest from its application in the treat- 
ment of many diseases. 

Electromechanism is an important branch, on account 
of its various applications in the arts. The invention of 
the electro-magnetic telegraph forms an era in the his- 
tory of human intercourse ; and the application of elec- 
tric currents as a source of motive power becomes in- 
vested with great interest when we consider that metals 
must sometime supersede coal, as a source of motive 
power. 

Q 



362 Physical Sciences. [Chap. XXIII. 

As heat is produced, transmitted, reflected, refracted, 
and polarized, precisely like light, and travels with near- 
ly the same velocity, we may infer that it, also, consists 
of undulations of ether : and the fact that we can obtain 
an indefinite amount of heat from a small body, by means 
of friction, leads to the same conclusion. 

Again, the close connection and marked resemblances 
between heat and electricity, indicate that the latter con- 
sists of ethereal undulations, as well as the former. 

Hence we come to the conclusion that the imponder- 
able agents are all essentially alike, and that their differ- 
ent phenomena arise from different kinds of undulations. 
This conclusion is strengthened by the close resemblance 
which the various phenomena exhibit, and the fact that 
one frequently produces another. The imponderability 
of all of them leads to the same conclusion ; for, as the 
weight is proportional to the mass, in all ponderable 
bodies, it follows that we cannot add solid matter indef- 
initely to a body without appreciably increasing its 
weight. The conclusion is further corroborated by the 
fact that the agents all follow the same law of intensity, 
which is uniformly as the inverse square of the dis- 
tance. (25) 

§ 4. Of the Organical Sciences. — Characteristics and Founda- 
tions of this Class. — Directions for Study. — Three important Prin- 
ciples. — Monsters. — (1) Botany. — (2) Zoology. — Caution. — (3) 
Anatomy. — (4) Physiology. — Hygiene. — Ethnology. — (5) Pathol- 
ogy. — Proper Bases of the Medical Arts. — Two guiding Principles. 
— Distinction. — Foundations of Pathology. 

These sciences are distinguished from the preceding 
by the general absence of long chains of reasoning, as 
they consist mostly of facts learned directly from obser- 
vations or experiments, which are frequently aided by 
the microscope, electric action, chemical re-agents, and 
so forth. A few observations, made anywhere, may serve 
for the foundations of most of the inorganical sciences : 
and when these foundations are once well laid, the rest 
consists chiefly of simple deductions. But those now 
under consideration sometimes require that the whole 
world should be ransacked, in order to furnish their ma- 
terials, as every country offers something peculiar; and 
long deductions here give place to extensive observa- 
tions, and a careful examination of testimonies. 

In studying these sciences, we should observe for otir- 



{Sec. 4.] Oeganical Sciences. 363 

selves, as extensively as our circumstances will permit. 
This will often enable us to obtain more accurate and 
lively views of the things discussed than mere descrip- 
tions afford, and possibly to correct the errors or extend 
the statements made in books. We must be constantly 
on our guard against erroneous testimonies and false 
theories, which have been very prevalent in this depart- 
ment of knowledge : and we should distinguish the as- 
certained facts from the plausible, but erroneous hypoth- 
eses with which they are sometimes blended. Mathe- 
matics are much less applicable in these sciences than in 
the inorganical, so that they may be studied to advant- 
age by persons who possess only a very limited knowl- 
edge of Mathematics. 

The principles of classification come frequently into 
requisition, and a proper application of them is gener- 
ally a matter of great importance, in all these sciences. 
They are, therefore, well adapted for investigation by 
those who dislike long chains of reasoning, and delight 
in observing and classifying, while they furnish a field 
which the united labors of many generations will not 
exhaust. 

In examining the structure of minute parts, much aid 
is derived from the microscope, which enlarges the power 
of vision to such an extent that it may be said to reveal 
new worlds: and although these are as diminutive as 
those unfolded by the telescope are extensive, yet they 
possess over the latter the great advantage of being com- 
pletely within our reach. 

In all the organical sciences, the following inductive 
principles guide and assist investigation. 

(a.) Every organ performs one or more functions. 
Those of some organs, such as the eye and the ear, are 
easily ascertained ; and although those of some parts are 
not so readily discovered, they may be found out by con- 
tinued and accurate investigation. Some organs, like the 
human tongue, perform different functions ; and, there- 
fore, when we discover one, we must not infer that it is 
the sole function. 

(b.) One part of an organic being harmonizes witii 
every other part / and the whole fabric is adapted to 
some particular mode of existence. Hence an inspection 
of one part, as a tooth or a foot, may enable us to ascer- 
tain the form of another, and the being's general struc- 
ture and mode of existence. 



364 Physical Sciences. [Chap. XXIII. 

(<?.) The corresponding organs of similar organic be- 
ings perform similar functions. Hence when those of 
one organ are known, those of the corresponding organ 
may be ascertained with little difficulty. The similarity 
of functions is generally proportional to that of the be- 
ings compared : and where this is very close, the func- 
tions are usually identical. 

These principles do not, of course, apply to monsters 
or malformations : but the existence of such beings is so 
rare as not to detract materially either from their value 
or their general accuracy. Such anomalies are extreme- 
ly few, compared with the wide extent of organic na- 
ture ; and even these arise from some violation of organ- 
ic laws. 

1. Besides the interest which it derives from the im- 
mense variety, beauty and magnificence of the vegetable 
kingdom, Botany claims attention on account of its bear- 
ings on the necessaries and conveniences of life. Not 
only our food, but also our clothing, is all derived from 
vegetation, either directly or indirectly. So is a great 
number of the most valuable medicines; and the various 
uses of timber are well known. By describing the qual- 
ities and peculiarities of the various kinds of plants, Bo- 
tany assists us in determining their character, the best 
modes of cultivating such as are useful or ornamental, 
and where any required species may be procured. 

The facts of this science are learned from observing 
the plants in their native regions, hot-houses or botanical 
gardens, or from examining preserved specimens, and 
from inspecting their minute structure with the micro- 
scope, while the component elements are ascertained by 
chemical analysis. (26) 

2. The boundaries between Botany and Zoology are 
not very obvious, as some animals are so low in the scale 
that they cannot easily be distinguished from plants ; but 
every being possessing thought is an animal ; and this 
criterion is easily applied, as thought is always accom- 
panied with the power of voluntary motion. 

Zoology describes the various kinds of animals, classi- 
fied according to their organization, including their ap- 
pearance, general structure, food, instincts, habits, and lo- 
calities : and a knowledge of it is indispensable to right 
views of the economy of nature. To the interests of Bo- 
tany, it superadds that which is derived from sympathy 



Sec. 4.] Oeganical Sciences. 365 

with living beings possessing several faculties in common 
with ourselves, although they are limited to a compara- 
tively narrow range. It facilitates a discovery of the 
characteristics of a hitherto unknown species, and enables 
us to determine the proper mode of treating the low- 
er animals, many of which have often been destroyed 
through ignorance, when they ought to have been care- 
fully preserved. 

The materials of this very extensive science are col- 
lected from direct personal observation, the reports of 
travelers, and the descriptions of naturalists, who lived 
in the native regions of the animals described, or had ac- 
cess to some fair specimens, such as are sometimes found 
in zoological gardens. But the proper criterions of tes- 
timony should be carefully applied to such descriptions, 
as several of them are blended with fables or misrepre- 
sentations. 

3. Anatomy furnishes a striking illustration of the con- 
summate skill with which everything throughout the or- 
ganic creation has been formed ; and it also demands at- 
tention on account of its connection with Physiology, 
Surgery and Medicine. It is based on careful dissection, 
aided by the miscroscope, mercurial injections, diluted 
acids or alkalies, &c. Human Anatomy exhibits a cor- 
rect view of the most complex and finished work of God 
that our eyes can behold. General and Comparative 
Anatomy shows the immense variety which prevails in 
animal structures, and the numerous modifications found 
in the same organ, adapting it to various circumstances. 
It also enables us to classify animals according to their 
real affinities, which often differ widely from apparent 
resemblances. 

4. Physiology is of the utmost importance on account 
of its connection Avith health, the laws of which seldom 
receive due attention from those who are ignorant of 
this science. Mere precepts have comparatively little in- 
fluence on such persons, as they readily evade what they 
are very unwilling to believe. But when they under- 
stand the nature of their physical organization, and the 
serious injuries which it "suffers from various agents and 
practices deemed harmless by the ignorant, prejudice can 
no longer resist the inference, and the rules of health 
soon change their habits for the better. Reckless ex- 
posure to deleterious agencies, and habitual indulgence 



366 Physical Sciences. [Chap. XX1LT. 

in health-destroying practices, gradually disappear, till 
they vanish : and the delusion of supposing that the ef- 
fects of such conduct can be obviated or speedily re- 
moved, is seen in its true light. This science also shows 
the extreme minuteness and perfect finish of the element- 
ary parts of every tissue. It discloses fibres compared 
"with which the most slender filament that we can see. is 
a cable, and globules of which it would require millions 
to form the size of a pea. 

The truths of Physiology are established by means of 
simple observations, and experiments of various kinds, in 
which much use is made of the microscope. It also de- 
rives extensive aid from Chemistry, Botany, Zoology and 
Anatomy, with the last of which it is very closely con- 
nected. 

Hygiene, or that part of Human Physiology which dis- 
cusses the laws of health, establishes these on the struc- 
ture and functions of the various parts, and the knowl- 
edge derived from observation or experiment regarding 
the modes in which they are affected by particular agents 
or practices. Health and disease depend on causes which 
act as uniformly as any agent in the inanimate creation ; 
and, consequently, wherever men fulfil the conditions on 
which it depends, they will enjoy health, while they will 
be the victims of disease and premature death as long as 
they violate these conditions. A knowledge of this part 
of the science is a most important means, not only of 
preserving: health, but also of curing disease, which can 
seldom be permanently and thoroughly removed, unless 
we know the conditions on which health depends. 

Ethnology, which discusses the origin and extent of 
the physical peculiarities that distinguish the various 
races of men, forms another interesting branch of Human 
Physiology. Detailed accounts of these peculiarities, as 
they are exhibited in different countries, properly belongs 
to Ethnography. 

5. The^leading principles of Pathology are highly use- 
ful in securing obedience to the laws of health, by dis- 
closing the various lamentable consequences which inev- 
itably result from their continued violation. This sci- 
ence also forms a proper sequel to Human Anatomy and 
Physiolosrv, in a course of medical study. Chemistry' 
and the organical sciences, form the only rational and sci- 
entific bases of the healing*arts, which are as apt to in- 



Sec. 5.] Pathology. 367 

jure as to benefit while they are merely empirical, and 
which improve in exact proportion to the advancement 
in those sciences. 

The pathologist is guided by the induction that mor- 
bid action obeys fixed laws, like healthy functions : and, 
consequently, he can ascertain the causes of such actions, 
and the modes in which they may be prevented or stop- 
ped, and their bad effects counteracted and removed. 
He is also aided by the induction that the reactions of 
the organism, caused by morbific agencies, tend to pro- 
duce some beneficial end: and it is an important object 
to ascertain what that end is, and how it can be best se- 
cured. He should distinguish the sanitary action which 
occurs in diseased parts from the injurious effects of pois- 
onous or deleterious agencies, which are of a very differ- 
ent character, although they are very apt to be confound- 
ed with the former, because they spring from the same 
causes, and appear simultaneously. While the latter 
should always be stopped and counteracted with as little 
delay as circumstances, and a due regard to other hy- 
gienic and pathological laws, will permit, the former 
ought generally to be fostered, and aided by all proper 
means. For their general tendency is, to rectify some 
derangement or disorder in the organism. 

This impoi'tant and extensive science is mostly estab- 
lished like Anatomy and Physiology : but it has a wider 
range, and derives more aid from the inorganical and 
geographical sciences, because disease is more varied in 
its origin, phases and progress than healthy action. It 
is beset with difficulties, whenever we pass beyond the 
immediate phenomena ; and the theories with which it 
abounds, furnish a wide field of investigation. 

§ 5. Of the Geographical Sciences. — General Character of this 
Class. — Directions for Study. — (1) Geography. — (a) General Geog- 
raphy. — (b) Geognosy. — (c) Hydrology. — (d) Meteorology. — (2) 
Chemistry. — (3) Mineralogy. — (4) Geology. 

These sciences treat both of inorganic and organic na- 
ture ; and consequently they resemble partly the mechan- 
ical and partly the organical. Although their subjects 
are less vast than those of Astronomy, yet they are not 
only much more within the reach of our observation, but 
also more on a level with our faculties ; and consequent- 
ly their phenomena are apt to affect us more powerfully 



368 Physical Sciences. [Chap. XXIII. 

than the vaster scenes of that science. They consist of 
an immense mass of primary facts, based on observations 
made in different regions of the globe, and of numerous 
inferences from these facts. Hence, in studying them, 
we should guard against fallacies both of testimony and 
reasoning. As personal observation enables us to test 
only a very small portion of them, the criterions of testi- 
mony should be applied with great care and freedom. 
In other respects, the remarks already made regarding 
the study of the other physical sciences, mostly apply to 
them. As a whole, they offer a very extensive field for 
future discovery. 

1. The immense variety and importance of its details, 
and their numerous applications, render Geography a 
very interesting subject of study ; and there is hardly 
any class of persons to whom a knowledge of it is not 
beneficial. 

(a.) General Geography forms the basis of all geo- 
graphical knowledge, and is of the greatest use in the 
irnpoi-tant arts of Surveying and Navigation. It is found- 
ed wholly on Mathematics and Astronomy. The exact 
positions of places on the Earth's surface are determined 
by finding their latitudes and longitudes, which may be 
done in various ways. 

As the elevation of the celestial pole, or immovable 
point in the heavens, is necessarily equal to the latitude 
of the place of observation, this may be found by taking 
the greatest and least altitude of a circumpolar star, or 
one which never sets : then half the amount of these 
gives the latitude, because the greatest elevation is as 
much higher as the least is lower than the pole. Anoth- 
er simple means of finding latitudes is, by taking the me- 
ridian altitude of the sun or a fixed star. As the zenith 
distance of the equinoctial is equal to the latitude, and 
the declinations, or distances from that line, are given in 
tables, a single meridian observation determines the lati- 
tude. 

The longitude of a place is found by ascertaining the 
difference in time between it and the first meridian, or 
that from which longitude is reckoned, and then convert- 
ing this into degrees, from the proportion of 15 degrees 
to an hour, every parallel revolving through 360 degrees 
in 24 hom-s. One of the most simple modes of finding 
the difference of time is, to mark the hour on a chronom- 



Sec. 5.] General Geography. 369 

eter which shows the time at the first meridian, when it 
is noon at the place of observation. This is known by 
the Sun's being then on the meridian, or at the highest. 
A more exact, but less simple and easy method is, to find 
the time at the first meridian from the Moon's distance 
from some fixed star, with the aid of tables, which give 
the distances of that luminary from many of the fixed 
stars, at short intervals. The time of the place of ob- 
servation may be found from one or two altitudes of a 
known fixed star, with the aid of tables. This method 
possesses the great advantage of being independent of 
time-keepers. Another simple and very accurate method 
is, to determine the difference of time by means of tele- 
graphic signals ; and the use of the electromagnetic tel- 
egraph renders this method applicable to all places con- 
nected by it. 

"When the positions of the principal points have been 
thus ascertained, those of others are found by means of 
geodetical surveys, conducted on the principles of spher- 
ical trigonometry, while minor details are found by means 
of plane trigonometry and constructions on paper. Maps, 
globes, and charts are then constructed, by applying the 
principles of perspective, and using the requisite mathe- 
matical instruments. 

That the Earth is either a perfect sphere or a spheroid, 
is evident from the form of its shadow on the Moon, dur- 
ing lunar eclipses, and from the distance of the visible 
horizon at sea being always nearly proj:>ortional to the 
elevation of the observer's eye. Its magnitude may be 
easily determined approximately, by measuring the an- 
gular depression of the farthest visible part of the ocean 
from a point of known altitude above the sea level, as 
we have thus the three angles and a side of a triangle to 
find the other sides. 

A more accurate method of finding the form and di- 
mensions of the Earth, is, to measure an arc of the me- 
ridian and of the parallels of latitude, in different parts 
of the world. In order to this, the difference of latitude 
and longitude between two places is accurately ascer- 
tained ; and then the distances between the two meridi- 
ans and parallels which pass through them are carefully 
measured : for it is easily seen that these distances bear 
the same proportion to the circumference of the Earth 
that the angular distances bear to 360 degrees, or an en- 
Q2 



370 Physical Sciences. [Chap. XXIII. 

tire angular circumference. It is thus found that the 
Earth is a prolate spheroid, whose respective diameters 
are about 7899 and 7925 miles : in other words, its form 
and magnitude are those of a solid generated by the rev- 
olution of an ellipse about its conjugate or shorter diam- 
eter, this being of the former, and the transverse, or lon- 
ger, diameter of the latter length. 

The absolute mass, or weight, of the Earth is ascei*- 
tained, approximately, in various ways. One is, by de- 
termining the influence of a mountain, in deflecting a 
pendulum from the perpendicular : but as the weight of 
the mountain and the distance of its center of gravity 
cannot be ascertained with any great degree of accuracy, 
this method gives only a rough approximation. A more 
accurate method is, to determine the comparative force 
of gravity, at different distances from the Earth's center, 
in the same vertical line, from the differences in the vibra- 
tions of a seconds pendulum, at the two points, whence 
the absolute gravity of the Earth is easily ascertained. 

A third method is, to compare the torsion produced 
by two large balls of lead on two very small ones, fixed 
on the ends of a very light rod, suspended by a very slen- 
der wire, and brought quite close to the large balls. The 
weight requisite to produce the same amount of torsion 
is easily ascertained ; and thus the proportion which the 
Earth's weight bears to the balls can be ascertained, to a 
great degree of accuracy. The extreme minuteness of 
the balls is compensated by their close proximity to such 
a degree as to render their influence measurable, the 
gravitating force being less as the square of the distance 
of the body's center of gravity becomes greater. By 
such means it is found that the Earth is about 5^ times 
as heavy as a globe of water of its own size, while the 
Sun's specific gravity is only about 1^. 

(b.) Geognosy lies at the foundation of several of the 
physical sciences, while it is indispensable to commerce 
and intercourse between remote nations. A knowledge 
of it may also enable the unfortunate and distressed to 
remove to a country where they can materially better 
their condition. It is also of great use in the study of 
Ethnography and History, which cannot be rightly un- 
derstood without its aid. It is founded on the observa- 
tions of naturalists, travelers, and mariners, made in the 
various quarters of the world. 



Sec. 5.] Geographical Sciences. 371 

(c.) Hydrology is of the utmost use iu Navigation, and 
furnishes means of extending our knowledge of Meteor- 
ology and Geology. Like the preceding subdivision, it 
is based chiefly on observation : but the causes of the 
tides are investigated by means of Dynamic and Astron- 
omy. These furnish a striking proof of the Earth's con- 
nection with other members of the solar system. 

(d.) Meteorology is of great importance in Hygiene, 
Therapeutic, Tillage, and Navigation. A knowledge of 
the atmospheric currents, combined with that of oceanic 
currents and the tides, enables the mariner to navigate 
the waters with a degree of speed and safety otherwise 
unattainable, while the electromagnetic telegraph ren- 
ders the knowledge thus acquired of the utmost practical 
utility, by warning vessels of the coming storm, before 
it arrives. So, an acquaintance with the laws of earth- 
quakes furnishes various means of preventing their ca- 
lamitous effects, by giving intimations of their future ac- 
tion. The materials of this extensive subdivision are de- 
rived mostly from direct observations, made with the aid 
of various instruments, including the anemometer, which 
determines the force and direction of the winds, the hy- 
grometei*, the thermometer, the barometer, the pluviame- 
ter or rain-gauge, the tide-gauge, and the seismometer, 
which measures the force of earthquake shocks. 

2. Chemistry affords an insight into the recondite 
structure and operations of nature, by disclosing the 
properties of its primary elements, and the laws of their 
combination and separation. It also bears an important 
relation to several other sciences, and to many of the 
arts. It enables the Physiologist to determine the com- 
position of secretions and tissues ; it unfolds to the Geol- 
ogist the composition of rocks ; and it gives the Botanist 
similar knowlege regarding plants. It is likewise of 
much importance in establishing proper rules of dietet- 
ics ; and it contributes to the improvement of tillage, by 
analysing soils, and showing what elements they possess 
or lack, and how they require to be cultivated, in order 
to yield abundant produce. 

The phenomena of Chemistry should be distinguished 
from their hypothetical explanations : the character of 
the latter does not affect the truths of the former, al- 
though their causes should continue as unknown as the 
cause of the yellow color of gold, or the sweet taste of 
suerar. 



372 Physical Sciences. [Chap. XXIII. 

This science is based chiefly on experiments, perform- 
ed by means of heat, electricity, light, and the mutual 
action of substances on each other. These experiments 
frequently require much ingenuity and manual dexterity, 
and a careful application of the most exact and reliable 
methods of determining quantity, with very delicate and 
accurate instruments. Many substances are of a com- 
plex structure ; and it is often no easy task to determine 
whether a compoimd, obtained from analysis, was not 
formed during the process, by a play of the affinities. 
Another difficulty arises from the extremely small amount 
of some constituent element, which yet greatly affects 
the character of the compound. 

3. Mineralogy is interesting on account of its applica- 
tions in mining, metallurgy, and the construction of op- 
tical instruments. It also exhibits the beauty and regu- 
larity of inorganic nature, in a peculiar manner, as every 
compound exhibits a characteristic geometrical form. 
This enables the mineralogist to determine the character 
of a mineral very easily, where a person ignorant of the 
science would be readily misled or deceived. He is in 
no danger of paying the price of a diamond for a piece 
of quartz crystal, of comparatively no value. 

The composition of minerals is determined by chem- 
ical analysis ; and the exact form of crystals may be as- 
certained by the goniometer, while Geology and Geog- 
raphy aid us in ascertaining where the various substances 
may be found. 

4. From shapeless masses of rocks and dirt, and the 
broken, and frequently petrified, organic remains imbed- 
ded in them, Geology unfolds the history of the Earth, 
and the numerous wonders which it exhibits. The ori- 
gin of seas and oceans, of the lofty mountains and the 
lowly vales, with their endless diversities, forms a sub- 
ject in which all intelligent minds must feel much inter- 
est ; and this is increased when we discover the agencies 
by which they were produced, and the organisms by 
which the Earth was formerly tenanted. 

This science is also very important in an economical 
point of view. It teaches us where to look for metallic 
ores, coal, building and earthenware materials, subterra- 
neous supplies of water, mineral manures, the precious 
metals, and gems. Much money and labor have been 
lost in searching and digging for such things, where 



Sec. 5.] Geographical Sciences. 373 

Geology would inform us that they were not to be found, 
while they have lain hid, for many ages, in favorable sit- 
uations, where it would have readily disclosed their ex- 
istence. It also assists us in determining the character 
and capabilities of soils, while the palseontological por- 
tion throws light on several difficulties in the organical 
sciences. 

The position, structure, and size of rocks, and of the 
organic remains found in them, are ascertained from im- 
pacting the face of the country in different regions, and 
the sections laid bare by flowing water, subterraneous 
agencies, or works of art. The investigation is much 
facilitated by the edges of the rocks having been very 
frequently exposed to view, along the surface of the 
ground, because they were tilted up from their first po- 
sition, either by the parts beneath giving way or by an 
upheaving force having been applied from below. The 
dip and strike of rocks are most easily measured with 
the compass and the clinometer, which is a simple mod- 
ification of the quadrant of altitude. Then, by measur- 
ing the horizontal thickness, at right angles to the strike, 
the real thickness is found by simply solving a right- 
angled triangle. The nature of the forces which pro- 
duced the phenomena, and of the organic remains found 
in the rocks, is ascertained by calling in the aid of Mathe- 
matics, and the other physical sciences, as may be requi- 
site. 

There is thus furnished a wide field for inferences, re- 
garding the circumstances under which those phenomena 
originated, and the actual condition of the Earth, during 
the various periods. The supposition that the Creator 
employed an endless series of miracles, in order to entrap 
us into false inferences, is manifestly absurd ; and, there- 
fore, geological phenomena are to be attributed to those 
agencies which are known to produce similar appear- 
ances at present, so far as these are adequate. When 
they are not, recourse must be had to the usual modes 
of ascertaining causes, in similar cases. (2 7) 



374 Mental Sciences. [Chap. XXIV. 



CHAPTER XXIV. 

OF THE MENTAL SCIENCES. 

§ 1. Of the Mental Sciences in General. — General Character of 
this Class. — Causes of their comparatively slow Progress. — Their 
principal Foundations, and Importance. — Why frequently under- 
valued. — Directions for Study. 

The mental sciences exhibit a wide range of primary 
facts, consisting partly of necessary and partly of contin- 
gent truths, while they abound with inferences. Many 
of their propositions are known by direct discernment, 
while others are established by an analysis of thought 
and motives, a process which is never employed in other 
sciences. Owing to the extreme rapidity of thought, to 
our performing several mental operations simultaneously, 
and to one thought's readily leading to another, this anal- 
ysis is generally attended with difficulty; and it is fre- 
quently necessary to have recourse to indirect means of 
effecting our object. Mere external observation is of lit- 
tle avail, in surmounting the chief difficulties. If to this 
we add that, owing to the manifest bearings of the points 
in question on our future condition, strong prejudices fre- 
quently interfere, we can easily understand why these 
sciences have made such slow progress, compared with 
some others. 

The principal foundations of the mental sciences are, 
immediate discernments, the conclusions of the physical 
sciences, and inductions from History or Biography. 
They are of the utmost imj^ortance, since they influence 
our condition much more extensively than any other di- 
vision of knowledge, and their principles are requisite to 
regulate our daily thoughts and conduct. They also 
greatly influence the condition of all other branches of 
knowledge. For the mind must receive that thorough 
discipline and those external advantages which only the 
proper study and general diffusion of these sciences can 
give, before it is in a condition to enlarge and improve 
to the utmost the other fields of human investigation, or 
apply them to their true objects. 



Sec. 1.] Uses and Study. 375 

The various departments of knowledge are so connect- 
ed that an improvement in one favors a corresponding 
advance in others ; and this is especially the case with 
that now under consideration, on account of its extensive 
influence in improving the mind, removing restraints on 
proper investigation, and furnishing the various other 
requisites to success. It teaches mankind the true value 
of knowledge, and at the same time disposes them to 
furnish the means for its successful cultivation, and points 
out how this object is to be secured. They also inure 
us to those habits of close attention to mental phenome- 
na and recondite, but important, distinctions, which are 
requisite to a proper solution of many practical problems 
of the utmost moment. 

These sciences also teach us the difficulties attending 
many of their applications, and thus obviate the dogma- 
tism into which those are incessantly falling who are ig- 
norant of these difficulties. A man totally ignorant of a 
mechanical art is apt to speak hesitatingly and distrust- 
fully regarding it, whereas those who are equally ignorant 
of the mental sciences, are apt to speak very confidently 
regarding points which require for their solution an ex- 
tensive knowledge and careful application of their prin- 
ciples ; and thus they often utter gross absurdities, with- 
out ever suspecting the error. 

The mental sciences treat of subjects which do not 
immediately affect the senses like those of Physics, and 
they are founded, in a great measure, on truths or phe- 
nomena familiar to all, whence we are apt to think that 
we know them sufficiently without study, or that they 
are of little consequence. Yet they require diligent 
study, in order to be well understood, while our views 
of their subjects mold our whole character, and conse- 
quently determine our general conduct through life, and 
our whole future condition, so that, if these views should 
be radically erroneous, correct and extensive knowledge 
on other subjects will only render a person more power- 
ful for evil, both to himself and to others. 

In studying the mental sciences, we should beware of 
adopting alleged or supposed, in place of real, intuitions 
or inductions, and guard particularly against fallacious 
reasoning, masked by ambiguous or obscure language. 
For this purpose, great attention should be given to the 
principal terms, which cannot frequently be rightly un- 



376 Mental Sciences. [Chap. XXIV. 

derstood without closely considering our own thoughts, 
and comparing them with the definitions, because the 
subjects are not palpable to our senses, and therefore ob- 
scurity and vagueness of style are more apt to occur, and 
escape notice, than in other sciences. 

The student should not only test the accuracy of the 
definitions, the credibility of the evidences, and the sound- 
ness of the reasoning, but he should carefully examine 
whether statements alleged to be truths of consciousness 
are so in reality. This is rendered the more requisite by 
the fact that direct discernment is very frequently ap- 
pealed to in every part of these sciences, while the state- 
ments cannot be rightly tested by any other means, as 
external observation or the testimony of others is of no 
avail. 

There is here little danger of misspending time in 
studying truths of no practical importance, as very few 
of the cognitions are of that kind : but we must particu- 
larly guard against adopting mere hypotheses or opinions 
as cognitions, because the former frequently usurp the 
place of the latter. We should also fix all the leading 
truths of these sciences distinctly and permanently in the 
memory, as otherwise they will be generally misapplied, 
overlooked or forgotten, and thus fail to secure their 
principal objects. 

§2. Of Logic and Psychology. — Boundary between these Sci- 
ences. — Importance of the latter. — How distinguished from Physi- 
ology. — Why not appreciated by many. — Modes in which its Con- 
clusions are established. — Directions for Study. 

Logic is confined to the intellect, and it treats of their 
products and objects rather than of the faculties. Hence 
it excludes some of the most interesting departments of 
Psychology, while it discusses various subjects quite for- 
eign to that science. The one treats of knowledge, and 
the other, of the mind and its faculties and susceptibili- 
ties. (2 8) 

Psychology is a most important science, because a 
knowledge of the powers, affections and laws of the mind 
is requisite to our forming accurate conceptions of our 
present duties and future destination, to determine what 
we ought to do, in many momentous cases, and to use 
our faculties aright, in our ordinary conduct. It dis- 
cusses the physical organs only so far as they regard 



Sec. 3.] Psychology. 311 

mental manifestations, while Physiology, on the other 
hand, views the latter only as they influence the former. 

As several of the truths of Psychology are made known 
to us by immediate consciousness, many fail to see the 
advantages of studying it systematically ; and when they 
do so, they are apt to fall into the error of thinking that 
they could not fail to discern, whenever it might be re- 
quired, every truth which they see to be self-evident as 
soon as it is clearly and accurately set before them, al- 
though History and Biography show the reverse. A 
proper study of this science is requisite, in order to un- 
derstand the laws and processes of the mind, and to avoid 
the grave errors into which we are very liable to fall 
when we adopt as truths conclusions formed without any 
careful consideration of the subject. The maxim that 
first impressions are not reliable, holds true of mental, as 
well as of physical, objects. 

Psychology appeals to our individual consciousness, at 
every step, except where it introduces other unexcep- 
tionable evidence : and it possesses the great advantage 
of being based chiefly on immediate discernments, from 
which inferences are deduced as in all other sciences. 

In studying this important science, Ave must beware 
of obscure language and dogmatic statements requiring 
proof, which is not given. Particular attention should 
be paid to the precise signification of terms, as there is 
no subject on which we are more liable to be misled by 
considering mere expressions, and overlooking what they 
denote. 

§ 3. Of Theology. — Sublimity and Importance of this Science. — 
How the chief Conclusions of Natural Theology are established. — 
Its Uses and Study. — Biblical Theology. — Its Evidences. — Inquiry 
regarding its Records, and their Purity. — Its Relation to the other 
Division. — Observations on Study. — Scripture Interpretation. — In- 
fluence of Prejudices. — Two Extremes. — Proper Course. 

In the sublimity of its subject, Theology occupies a 
much higher position than any other science. Although 
the subjects of Astronomy are so vast as to transcend 
the powers of adequate conception, yet they are only 
masses of inanimate matter, inane as the empty void. 
Theology, on the contrary, investigates the existence and 
character of the Eternal Rulei*, who formed and governs 
all : and the light which they throw on his attributes, 



378 Mental Sciences. [Chap. XXIV. 

constitutes the greatest value of Astronomy, and all the 
other physical sciences. 

The importance of Theology is not inferior to its sub- 
limity. A knowledge of God's character forms the found- 
ation of all true religion, which is necessary to save man- 
kind from the horrors of superstition and practical athe- 
ism, and our views of which determine our condition 
through eternity, compared with which the longest life 
shrinks to nothing. Religion affords consolation when 
nothing else can ; and it is the only thing that furnishes 
enjoyments which will never fade nor cloy. It also leads 
to the performance of many important duties which no 
other motive will secure, so that it is as indispensable to 
steady good conduct as it is to permanent happiness. 

Our views of the Most High sway the whole circle of 
our thoughts and actions. For, when a man learns and 
bears in mind the true character of the Eternal, his own 
is gradually improved and elevated, by being assimilated 
to the object of his constant affection, admiration and 
reverence, while he who continues ignorant and regard- 
less of this subject, generally becomes the slave of appe- 
tite, debasing desires or malignant and selfish feelings, 
and proceeds from bad to worse. Hence the existence 
and character of God, and the relation in which we 
stand to him, as accountable, guilty and immortal beings, 
are matters to which every one should devote a very 
careful, diligent and impartial examination, and on which 
we should particularly beware of assuming that anything 
is either true or false, without conclusive proof. 

The existence of the Deity forms the first object of at- 
tention, in Natural Theology. It is proved by the phe- 
nomena of nature, both animate and inanimate, since ev- 
ery supposition which attempts to account for these, 
without a forming and presiding Intelligence, involves 
demonstrable impossibilities. The character of God is 
proved by the endless displays of incomprehensible skill, 
power and benevolence, which are manifested through- 
out the whole creation. 

Natural Theology strengthens the foundations of re- 
ligion and morality, while it furnishes much exalted en- 
joyment, by giving us correct views of the works of the 
Creator, and thus enabling us to participate in his joys, 
to the extent of our comparatively limited capacities. A 
knowledge of its principles also furnishes important aid 



Sec. 3.] Theology. 379 

in rightly interpreting the language of Revelation, which 
assumes these principles as known, or at least knowable, 
independently of its own teachings. 

The elements of this division may first be learned from 
books, after which we may continually enlarge our knowl- 
edge of it, by observing nature, both rational and irra- 
tional, with the aid of the principles previously acquired. 

In Biblical Theology, the evidences of Revelation form 
the first subject of consideration. They lie in the nature 
of the truths revealed, and in historical narratives which 
are tested by the ordinary criterions. We are then to 
inquire what are the genuine records of Revelation, in 
order that we may distinguish them from spurious com- 
positions, which falsely claim to form a part of them. 
We should also examine the purity of the text of those 
records, by means of the rules regarding written testi- 
mony, and also ascertain the precise limits of Revelation. 

After disposing of those preliminary matters, we are 
to examine what Revelation declares. It is, of course, 
consistent with the conclusions of Natural Theology: but 
it goes much farther, and teaches us various things on 
which Natural Theology sheds no clear light. 

The doctriues of Revelation exert a peculiar elevating 
and purifying influence on those who really understand 
and believe them, owing both to the impressiveness of 
direct communications from the Supreme Being, and 
their thoroughly reformatory and exalting character. 
They fail to produce such effects only upon those whose 
reception of them is merely nominal, or who modify and 
corrupt them, to suit their evil wishes. The teachings 
of Natural Theology are not sufficiently authoritative 
and powerful to produce, by themselves, those changes 
in the conduct and feelings of mankind which are essen- 
tial to their permanent welfare. 

As the whole of revealed religion is contained in the 
Sacred Scriptures, they should form the principal subject 
of our study of this division of the science. The charac- 
teristic benevolence of the Most High is shown in their 
being well adapted to the comprehension of every class 
of sane minds : and although some parts are obscure to 
the unlearned, these form but a small portion of the whole. 
All the principal doctrines are expressed and illustrated 
so clearly and variously, that no diligent student, who is 
desirous of knowing the truth, need misunderstand them. 



380 Mental Sciences. [Chap. XXIV. 

Much assistance may be derived from various other 
works, if judiciously used : but, whenever we have re- 
course to them, we should beware of fallacies of testi- 
mony, misinterpretation of language, and appeals to au- 
thority. We should never forget that Scripture is its 
own best interpreter, and that many works which pro- 
fess to unfold the doctrines of Revelation, teach most 
pernicious errors. These we may avoid by a careful and 
continued study of the Scriptures, which contain the only 
infallible authority on this subject, and on a right under- 
standing and belief of whose principal doctrines depends 
our eternal all. We should also bear in mind that one 
fundamental error may mislead us fatally regarding the 
whole subject, because the essential doctrines are so con- 
nected and dependent that we cannot have right views 
of some if we are radically mistaken regarding others. 

The Bible is interpreted by the ordinary rules of in- 
terpretation, since we are evidently addressed in the or- 
dinai'y language of mankind, which we can best under- 
stand, and neither in that of mathematicians nor of en- 
thusiasts. The style is often figurative or poetical : but 
the figures are such as occur in all impassioned discourse, 
and are employed with great uniformity. Consequently 
the language is generally more intelligible than if it had 
been more literal, because, in the long lapse of time, the 
latter would have changed more, while its variations 
would have been less obvious. The occult senses, pro- 
fessed to be found in the Scriptures by the Cabalists 
and other mystics, are only the dreams of imbecile un- 
derstandings. 

Throughout our study of this most important subject, 
we require to guard carefully against the influence of 
prejudices, as there is none on which they are more apt 
to mislead us. These are the main causes of the great 
diversity of religious belief that has hitherto prevailed 
among mankind, and not the inherent difficulties of the 
subject, which is by no means the most abstruse or dif- 
ficult branch of human investigation. 

On the one hand, multitudes have adopted supersti- 
tious and demoralizing doctrines, because they form part 
of the parental creed, and offer an easy and grateful road 
to future bliss. On the other hand, many have been led 
by such doctrines, and the corresponding practices of 
their votaries, to discard all revealed religion as a delu- 



Sec. 4.] Morality. 381 

sion or imposture, because they do not care to search 
into the real state of matters, or to see themselves as 
they actually are. Both classes are alike in desiring to 
shun the labor of proper investigation, and the sacrifices 
which a knowledge of the truth might impose. Hence, 
the former believe without any satisfactory evidence, and 
the latter reject conclusive proofs without an impartial 
examination. 

Nature and Revelation are evidently the only reliable 
sources of religious knowledge : and, therefore, whatever 
is inconsistent with their teachings, or not legitimately 
proved from either, should be rejected. But, before re- 
jecting any doctrine, we ought to know that it belongs 
to this class. On the other hand, whatever is proved by 
either, should be firmly and unhesitatingly believed. 

§ 4. Of Morality, ok Ethical Science. — Subjects and Founda- 
tions of Morality. — What it aims at effecting. — Its Advantages. — 
Directions for Study. 

This science first inquires into the nature and founda- 
tions of duty in general, and afterwards discusses the va- 
rious kinds of duty specially. It derives its principal 
primary premises from Psychology, Theology, and Phys- 
ics, although it also employs various truths derived from 
other sources. 

To determine beforehand the duty of a person, in ev- 
ery combination of circumstances that can arise, is im- 
practicable, since these are endlessly diversified. But 
we may establish principles, which apply to all cases, 
and discuss their chief applications, so that the precise 
line of conduct which duty requires, may be distinctly 
laid down, in all important cases of frequent occurrence. 
When once we clearly understand both a principle and 
its leading applications, we can generally, without diffi- 
culty or inconvenience, determine its other applications, 
since they are always very similar to those already 
known. 

The belief that the mind comprehends the nature of 
right and wrong, as the eye perceives the distinctions of 
color, is refuted by the diversities of opinion which have 
prevailed among mankind on many moral questions. 
Were that belief correct, there could be no more differ- 
ence of opinion as to whether a certain course is right, 
than there is about the color of the sky or the taste of 



382 Mental Sciences. [Chap. XXIV. 

sugar. On the contrary, what is right and wrong can- 
not frequently be determined without a proper applica- 
tion of moral principles, which are established only by a 
close investigation of several subjects by no means free 
from difficulty. 

The Holy Scriptures are designed to aid, and not 
to supersede, the use of our faculties; and, therefore, 
they leave many important questions to be answered by 
our own investigations. Thus, we are commanded to do 
to others as we would have them do to us : but we are 
not told whether our actual or our reasonable wishes 
are the test. We can solve such questions readily with- 
out the aid of Revelation ; and it is evidently no part of 
the plan of Providence to encourage indolence, and fos- 
ter mental imbecility, by solving for us problems which 
we can easily solve for ourselves, by a proper application 
of our faculties. 

Morality discusses the whole subject of duty, once for 
all, and thus guards us against the various dangers inci- 
dent to sitting down to solve moral problems, when we 
ought to be acting. A man who has never considered 
what his duties are, until he is placed amidst the circum- 
stances in which he is required to act, is very apt to con- 
vince himself that what he is strongly tempted to do, is 
right, whereas, if he had previously examined the sub- 
ject, while he was free from any such excitement, he 
would see it in its true light, and the settled view, thus 
obtained, would enable him to resist the temptation, and 
to act as duty dictated. Unprincipled or immoral con- 
duct is caused, in no small degree, by failing to consider 
what duty requires, till the time for action comes, in con- 
sequence of which the passion or appetite of the moment 
controls the conduct. 

The influence of prejudices is never more powerful than 
when we examine what duty requires, with reference to 
objects of strong desire, while these are placed in full 
view. For we inevitably see distinctly the sacrifice that 
must be made, in the event of our conclusions being hos- 
tile to the gratification of the desire. Hence the great 
advantage of ascertaining what our duties are, before 
such desires have been thus excited, as their influence is 
thus rendered comparatively feeble. 

In studying Morality, the learner should first obtain 
clear and accurate conceptions of the nature and sane- 



Sec. 5.] Jurisprudence. 383 

tions of duty in general, and afterwards investigate the 
fixed and certain relations which the various classes of 
duties bear to his present and future condition. In or- 
der that this science should produce its legitimate effects, 
it is not enough to read or hear that we should do this 
and not do that : we must cleai*ly see the sure and inev- 
itable consequences of so doing, and then fix them dis- 
tinctly and permanently in the memory. 

§ 5. Of Jurisprudence. — Nature, Foundations, and Uses, of this 
Science. — How related to Legislation. — Practical Application. — 
Importance of discussing Principles in the abstract. — Study. 

Jurisprudence resembles Morality in its processes : but 
it considers man only as the subject of political govern- 
ment ; and, therefore, it is much narrower in its range. 
From premises obtained chiefly from Psychology, Moral- 
ity and History, it deduces the laws best adapted to man, 
in a normal state, or that condition in which the commu- 
nity are enlightened, and attentive to everything that se- 
riously concerns them, whether present or future. 

A knowledge of this science is requisite in order to 
understand the true functions, influence, and powers, of 
government, regarding which many have formed very 
erroneous views. On the one hand, calamities have been 
attributed to misgovernment, which were wholly owing 
to other causes, while things have been expected from a 
good government which the best cannot confer. Mis- 
government is itself an effect of evils which previously 
existed ; and these may continue to exist under any gov- 
ernment, as their removal requires more potent agencies 
than human laws. On the other hand, the sufferings pro- 
duced by bad laws, or the abuses of power, have often 
been wickedly laid to the charge of Providence. 

It is necessary to understand the elements of Juris- 
prudence, in order to form correct opinions regarding 
the nature of true liberty and individual rights : and a 
citizen cannot secure his own rights, or perform his duty 
to his country, unless he knows what the former are, and 
what measures the public welfare requires. 

Jurisprudence in the mental sciences resembles Hygi- 
ene in the physical. The Hygienist deduces the laws of 
health from a knowledge of the human organization and 
the nature of the agents that affect it : his conclusions 
are not in the least invalidated by the fact that many are 



384 Mental Sciences. [Chap. XXIV. 

ignorant of those laws, that several are too much under 
the influence of bad habits to obey them perfectly, even 
after they have been clearly set before them, and that 
others have contracted diseases which render medical 
treatment desirable. So the jurist deduces the principles 
of his science from a knowledge of the mental character- 
istics of man, and the agencies by which they are affect- 
ed. Many, or possibly most, nations may be too igno- 
rant, prejudiced, or oppressed, to adopt those principles 
to any great extent. Yet much is effected by clearly es- 
tablishing them : for when a people who possess any con- 
trol over their laws and government, see clearly what 
duty and their true interests demand, they will take some 
steps in the right direction, and these will prepare the 
way for more, until at length their institutions will be- 
come conformed to the principles of Jurisprudence, al- 
though such a consummation may require many genera- 
tions. 

The duties of the legislator differ from those of the 
jurist. It is the duty of the former to propose only such 
changes as the nation are likely to sustain and carry out 
in practice : for, if he were to go farther, the innovations 
would be only a dead letter. Every step in the direc- 
tion, however, is a gain, provided it be real, and there be 
no subsequent retrogradation. The jurist, on the other 
hand, aims at establishing scientific principles, applicable 
in every age and country, independently of any particu- 
lar changes or circumstances. 

When a law is found to be defective, an application of 
the previously established principles of this science to 
the circumstances of the case, indicates the change which 
ought to be made : and, without such guidance, changes 
would be as likely to deteriorate as to improve : for they 
would either be made at haphazard or under the influ- 
ence of strong prejudices, excited by discussing juridical 
principles for the first time, in connection with the con- 
templated changes, and the numerous real or supposed 
interests which they involved. But when those princi- 
ples are first established and understood, without any ref- 
erence to party questions or passing events, the changes 
which ought to be made, may be ascertained without 
any extraordinary difficulty, since all parties then stand 
on the ground of established principles, so that prejudices 
are allayed, and the means furnished for rightly determ- 
ining the matter in question. 



Sec. 1.] Philology. 385 

Before commencing the study of this science, the 
learner should master the principles of Morality, without 
a knowledge of which Jurisprudence cannot be studied 
with success. He should then acquire correct views of 
the foundations, legitimate functions, and proper limits 
of government and law : and he should always distin- 
guish the existing laws from the principles of this sci- 
ence, with which they have often been confounded. He 
should also distinguish Jurisprudence from Morality : 
for, although the two are closely connected, they are by 
no means identical. Our duty to others often requires 
from us much more than human laws can prudently de- 
mand, and much less enforce, while these laws take no 
cognizance of the still more extensive and important class 
of duties with which others have no direct concern. (29) 



CHAPTER XXV. 

OF MIXED KNOWLEDGE. 

§ 1. Of Philology. — Two modes of learning a Language. — Ultimate 
Sources of Knowledge regarding dead Languages. — Grammars 
and Dictionaries. — Usages. — Authorities. — Branches subsidiary to 
Philology. — Etymologies. — Requisites to knowing a Language. — 
How best attained. — Various Significations of Words. — Common 
Error. — Conversation and Composition. — Comparative Philology. 
— Its leading Principles and Eesults. — Affinities of Languages. — 
General Philology. — Uses of Philology. 

A language may be learned either by simply observ- 
ing spoken usage, or by means of special instructions 
from others, in a language which we already understand. 
The elements of the vernacular are necessarily learned 
by the former method, in the manner already pointed 
out ; and the youth can afterwards learn, from direct in- 
quiries, the exact significations of the more abstruse, rare 
or vague terms ; or he may consult grammars, dictiona- 
ries, and scientific treatises, for that purpose. 

The ultimate sources of knowledge regarding a dead 
language are chiefly the following: (1) Living Lan- 
guages which resemble the dead. (2) Translations made 
into some living or known language, by persons who 
learned the dead from spoken usage. (3) Grammars or 
dictionaries written by such persons, in some known lan- 

Pv 



386 Mixed Knowledge. [Chap. XXV. 

guage. (4) Historical compositions which relate events 
known to us through some other source. (5) A com- 
parison of works of ancient art with the descriptions or 
allusions of authors. These sources frequently make 
known the significations of all the more common words, 
inflections and constructions, after which reading good 
authors will farther extend our knowledge, since we can 
now learn the exact significations of many words and 
phrases from the context. The learner might now com- 
pose a grammar and dictionary of the language, and thus 
greatly facilitate and abridge the labors of succeeding 
students. 

After having obtained a good general knowledge of 
the language, by either or both of those methods, we can 
test the correctness of grammars and dictionaries, by an 
appeal to the best usage, or the practice of those who 
spoke, or still speak, the language in its utmost purity. 
Hence the greater value of dictionaries which quote pas- 
sages from reputable authors, since they enable us, in a 
great measure, to test directly the accuracy of their own 
definitions. 

In consulting such dictionaries, we should observe the 
age and character of the authors quoted. Some may 
have written at a time when the language was rude and 
uncultivated, and others, after it had become corrupted 
and debased. Loose thinking and acting generally pro- 
duce loose speaking : and hence a decline of morals and 
science is followed by corresponding deteriorations of 
language. Some authors, again, are above, and others 
below, the average of their age : and, therefore, we must 
consider their particular characters, as well as their age, 
in order to determine their value as authorities. The 
lexicographer should point out all the common significa- 
tions of terms, whether the usage be good or bad : but 
he ought to indicate the nature of the usage, with respect 
both to age and character, especially where his work is 
designed to aid learners in composition : and those dic- 
tionaries in which this is properly done, are generally 
very superior to others, on all important points. 

Among different reputable usages, the best is that 
which best answers the ends of speech : but that of per- 
sons who know the language well, and use it carefully, is 
to be deemed good. In cases of doubt or difficulty, re- 
course should be had to unexceptionable authority, and 



Sec. 1.] Philology. 387 

the definitions of the dictionary tested by it, as far as 
may be requisite. Wherever circumstances excite any 
suspicion of" misquotation, we should refer to the origin- 
al passage, and the part quoted should be compared with 
the context. 

We should distinguish between treatises written by 
philologists who conversed long and freely with those 
by whom the language was correctly spoken, and au- 
thors whose knowledge of it is derived wholly from 
books. The former are themselves authorities : the lat- 
ter are not ; and the credit due to them depends wholly 
on the character of the books which they have read, and 
the use which they have made of them. Hence their 
statements are not entitled to be implicitly received, 
without proof, in any case of doubt or difficulty. Philo- 
logical treatises written by such persons sometimes con- 
tain various errors. Thus, we are told, in Greek Gram- 
mars, that, besides the active and the passive, there is a 
middle voice, representing only actions which the sub- 
ject of the verb does to himself. But when we come to 
examine the real usages of the language, we find that 
every one of the so called middle forms is either active 
or passive in signification, and represents actions done 
to others, as well as to the subject. Consequently the 
middle voice is wholly imaginary. 

The acquisition of a language is facilitated by an ac- 
quaintance with the ethnography and history of the peo- 
ple who originally spoke it, without which many idi- 
omatic terms and expressions cannot be rightly under- 
stood. 

The etymology of a derivative generally indicates its 
signification, since most derivatives closely follow certain 
rules which prevail in the language, so that a knowledge 
of the proper rule of derivation, and of the signification 
of the root, teaches us the signification of the derivative, 
without reference to any definition. Thus, if we know 
what good and hunt signify, we do not require to be told 
what goodness and hunter denote. There are numerous 
exceptions, however, chiefly in nouns, although some oc- 
cur in other parts of speech : and, consequently, etymol- 
ogy is by no means an infallible guide. 

To know a language, we must be acquainted with the 
signification of its words and phrases, and with their in- 
flections, constructions and collocations. The last three 



388 Mixed Knowledge. [Chap. XXV. 

are best acquired, in the first instance, from a good gram- 
mar, as any other course would require the labor of many 
years. After acquiring the simple elements of grammar, 
we should learn the exact significations of all the com- 
mon words, except those numerous derivatives regard- 
ing whose import we cannot hesitate or err. These are 
best learned from a classified vocabulary, accompanied 
with short and easy sentences, containing the words, in 
various forms. We should then master the rules of com- 
position and derivation, after which we shall know the 
signification of most of the common words, as soon as 
we hear or see them. Words of rare occurrence need 
not occupy our attention till Ave meet with them in dis- 
course. 

In ascertaining the significations of such words as oc- 
cur in various senses, we should first find the single pri- 
mary signification which every such word bore, and then 
learn the secondary or derived significations, and trace 
the steps by which they arose from the former. This 
will both aid remembrance, and prevent us from con- 
founding the senses. Very few words have more than 
three or four significations really different. But an ex- 
pression which bears only one meaning in its own lan- 
guage may require to be rendered by several in another, 
owing to differences of idiom ; and hence lexicographers 
sometimes render it in all these ways, without adverting 
to the fact that some of the significations were purely 
figurative, and that the language of translation made dis- 
tinctions Avhich were not made in the original. Hence a 
multitude of imaginary significations are found in old 
dictionaries, while the primary is frequently omitted, or 
not distinguished from others. The best philological 
works of the present day are distinguished by marked 
improvements in these respects. 

After thus acquiring the elements of the language, the 
learner should carefully peruse good authors who wrote 
in it, just as he would read works composed in his ver- 
nacular : and, while thus occupied, he should acquaint 
himself with those parts of the grammar which he had 
not previously studied. If he were to commence read- 
ing regular compositions sooner, his progress would be 
very slow and tedious, as he would require to be turning 
incessantly to his dictionary or grammar ; and he would 
frequently fail to learn the true significations of a word, 



Sec. 1.] Philology. 389 

after looking it up many times, because his mind "would 
be distracted by the various renderings given, his attend- 
ing chiefly to the passage before him, and long intervals 
elapsing between the references. 

If the learner require to write and speak the language, 
he should use it extensively in composition and conver- 
sation : but when he requires only to read it fluently, he 
need not spend much time in this way. 

After acquiring a knowledge of several languages, we 
may compare them, and note their resemblances and di- 
versities. 

Two languages may be found to be similar in their 
words, but different in their structure, like Latin and 
French. This indicates that both have a common origin, 
and that one has undergone great changes, either from 
having been adopted by a foreign people, or from exten- 
sive intercourse or intermixture with another race. The 
language superseded will be indicated by the structure 
or various words and idioms which it has communicated 
to its successor. 

"Where several languages are very similar, both in 
words and structure, it is to be inferred that they are the 
kindred offspring of a common parent, from which they 
sprung at a comparatively recent period in the annals of 
mankind. No very definite line of demarcation separates 
mere dialects from closely cognate languages. The best 
distinction appears to be, that whenever the parties who 
speak them, understand each other without an inter- 
preter, they are to be held only different dialects : other- 
wise they are to be deemed different languages. 

If various languages exhibit a close resemblance in 
structure, but great diversity in their words, it is to be 
inferred that they had a common origin, and that they 
have been little affected by foreign intercourse, but that 
those who speak them have had little intercom-se with 
each other. A good instance of this kind is furnished 
by the aboriginal languages of America, which all exhibit 
the same polysyllabic and polysynthetic structure, amid 
great diversities in their vocabularies. 

Where languages greatly differ, both in words and in 
structure, yet exhibit points of resemblance which can- 
not be attributed either to chance or intercourse, it is to 
be inferred that they have had a common origin, but that 
they have either been altered by foreign intercourse, or 



390 Mixed Knowledge. [Chap. XXV. 

that those "who speak them have been long separated, or 
that the original language, and consequently those who 
spoke it, were quite rude. 

The following are some of the conclusions deducible 
from the application of the preceding principles. 

(1) All the languages of mankind have gradually- 
sprung, by natural means, from a common origin, which 
has long disappeared. (30) 

(2) They are divided into great families, the members 
of which exhibit much closer affinities with each other 
than with those of any second family, whence it is to be 
inferred that the various families originated from a com- 
mon source, subsequent to the general dispersion of man- 
kind. 

(3) The families are often subdivided into groups, the 
members of which are marked by peculiarly close affini- 
ties. Some of these groups contain many, and some, 
only a few languages. 

(4) Some exhibit every appearance of having gradual- 
ly descended from the primitive source, by the changes 
naturally incident to human speech, without having ever 
been much affected by foreign elements or intercourse, 
while others have become so extensively blended with 
extraneous words, and changed in their structure, by for- 
eign influences, as to have passed rapidly into new and 
widely different languages. The former may be termed 
original, and the latter, composite languages. In the 
case of the latter, the elements of the original language 
continue to form the basis or framework of the resulting 
speech, although the new materials may form the larger 
portion of the whole. 

In order to ascertain the affinities of a language, it is 
unnecessary to learn all its anomalies and words. Its 
general structure and inflections, and the nature of the 
primitive words, determine its whole character. 

After acquiring a knowledge of several languages be- 
longing to the most dissimilar families, we can ascertain 
the principles and structure of language in general. Sev- 
eral works on this subject present erroneous views, as 
their authors were acquainted only with a few languages 
of similar structure. Yet good works on this subject 
are of much use, even to those who understand only the 
vernacular. They not only tend to improve style, but 
also facilitate the detection of several fallacies arising 



Sec. 2.] Ethnography. 391 

from language. Although philologists take good usage 
as their guide, yet they react powerfully on that of future 
generations : and their labors do much, not only to fix, 
but also to simplify, language, and to check, or even re- 
move, defects and anomalies. 

The knowledge of a foreign language enables us to 
consult works composed in it, and to hold oral or written 
intercourse with those who employ it. The language of 
a nation is also, in many instances, the only evidence of 
its origin ; and it exhibits various peculiarities regarding 
its circumstances and character, which cannot frequently 
be learned from any other source. Comparative Philo- 
logy removes various difliculties and obscurities attend- 
ing the study of dead languages. It also furnishes means 
of determining the origin, migrations and affinities of na- 
tions, and thus frequently supplies defects in History. 

§ 2. Of Ethnography. — Foundations of Ethnography. — Sources of 
Errors. — How these may be detected. — Uses of Ethnography. 

Ethnography consists chiefly of primary facts, derived 
from public records, the narratives of travelers, local his- 
tories, works of art, and direct personal observations. 
Owing to the immense extent of the subject, the latter 
can form only a very small part of it. The facts are also 
liable to change, more or less, from age to age, or even 
from year to year : and hence the accounts of the past 
may not apply to the present. Various errors have also 
arisen from the national or individual prejudices of those 
from whose works a great portion of ethnographical 
treatises is derived. Hence many of them teem with er- 
rors. But these may generally be detected by compar- 
ing the statements of various writers with each other, or 
by having recourse to original and reliable authorities. 
Those who write from their personal knowledge are gen- 
erally more reliable than such as derived their informa- 
tion from others : but there are great differences, in these 
respects ; and we may generally trust more to the care 
and veracity of an author than to his means of acquiring 
knowledge. 

A competent knowledge of Ethnography is requisite 
to a proper understanding of numerous statements and 
allusions found in the works of authors who treat of 
times or countries other than our own. It is also indis- 
pensable to the proper study of History, while it tends 



392 Mixed Knowledge. • [Chap. XXV. 

to remove the narrow-mindedness which is apt to accom- 
pany an acquaintance with only one state of society. It 
enables us to compare and trace the effects of different 
laws, opinions, institutions and manners. Thus we can 
form a proper estimate of our own condition, while we 
receive suggestions for its improvement. By the same 
means, also, we can easily avoid the dangerous error of 
assuming that our own morals, manners and institutions 
are perfect standards of excellence, when, in reality, they 
may be far otherwise. We also learn the wants of oth- 
ers, so that we can take proper steps to supply them. 
Besides these advantages, Ethnography answers several 
of the same purposes as Geography, to which it is close- 
ly allied. 

§ 3. Of Technology. — How an Art is distinguished from a Science. 
— Foundations of Art. — Its Relations to Science. — Requisites to 
Proficiency. — Superiority of Arts based on Inductions. — Theory 
and Practice. — Manual Dexterity. — Source of Improvements. — 
Importance and Relations of Rhetoric. — Education. — How related 
to Rhetoric. — Its Importance. 

An Art is distinguished from a Science chiefly by its 
consisting of rules and directions for effecting some ob- 
ject, and a general absence of discussions regarding sim- 
ple knowledge. Art considers how a certain thing is to 
be done, while science shows what is. Yet, as the prop- 
er mode of accomplishing a certain end, depends on a 
knowledge of the subject, and this must often be discuss- 
ed in a treatise on the art, the boundaries of Art and Sci- 
ence are not always well defined. Many sciences include 
what might properly be termed arts. Thus, G-eometry 
includes the art of drawing geometrical figures, and 
Astronomy, that of making astronomical observations. 
Such arts are properly classed with the sciences to which 
they refer, when they form necessary parts of them. 

Art borrows the knowledge which it requires from 
whatever sources afford it; and it often gives some de- 
gree of connection to a great many scientific elements, 
which have not been incorporated into any regular sci- 
ence. As new applications of the sciences may be made, 
without any increase of their number, the arts generally 
multiply much faster than the sciences. Several arts 
may be based on a single science; and, on the other 
hand, a single art often derives materials from several 
sciences. 



Sec. 3.] Technology. 393 

The dependence of Art and Science on each other is 
often mutual. The art of the optician is necessary to 
unfold the mysteries and wonders of the physical crea- 
tion, whether in the Sun or in a mite, while the optician 
is dependent on the sciences of Geometry and Optic. 
The value of the air-pump is felt in several sciences ; 
and the art of calculation is required in a still greater 
number. On the other hand, Art is based, more or less, 
on Science ; and it is generally impracticable to master 
any division of the former without acquiring some knowl- 
edge of the sciences on which it is dependent. This and 
careful practice are the principal requisites to proficiency 
in an art. 

While we act only on empirical knowledge, improve- 
ments must be accidental, and one advance does not pre- 
pare the way for another, as all empirical arts are neces- 
sarily chained down to one uniform course, and anything 
beyond the usual routine is out of the question. On the 
other hand, if we are guided by inductions, our processes 
are more certain in their results, and more susceptible of 
improvement, because we are in possession of the gener- 
al law. Thus, the mere fact that a certain medicine has 
been found beneficial in certain cases, does not inform us 
what are the circumstances on which its efficacy depends, 
or what are the principles of its operation : and conse- 
quently we should be apt to use it where its effects would 
be positively detrimental. So, .if a shipbuilder finds that 
a vessel of one form sails faster than another, of a differ- 
ent form, this knowledge does not enable him to make 
any improvements, while a knowledge of Mechanic and 
Hydric would unfold the principle on which the superior 
sailing depended, and thus enable him to build vessels of 
a still better form. 

A thing cannot be good in theory and bad in practice : 
for this is only saying, in other words, that rules based 
on a wide and correct knowledge of the subject, are in- 
ferior to those founded on narrow and inaccurate views. 
We should not confound what is really with what is only 
apparently good. A theory may be very plausible, and 
yet quite erroneous, just as an argument may be very 
specious, and yet quite fallacious : but a theory which is 
bad in practice, is bad altogether ; and, therefore, what- 
ever is really good in theory must be equally so in prac- 
tice, if it can be put in practice. The empiric thinks that 
R2 



394 Mixed Knowledge. [Chap. XXV. 

he alone is guided by experience, when, in truth, he is 
only guided by a narrow experience, while those whom 
he decries are guided by scientific generalizations. He 
also falls, in many instances, into the further blunder of 
mistaking his own erroneous inferences for the voice of 
experience. This teaches us simply what we have expe- 
rienced : and, in order to apply it safely to the future, 
we must reason on the subject, or, in other words, have 
recourse to theory. 

Although a certain degree of practice and manual 
dexterity often requires to be combined with theoretical 
knowledge, in order to render a person an adept in the 
art, yet the former, without the latter, is generally of lit- 
tle avail. Thus, a man ignorant of Anatomy and Physi- 
ology cannot be a good surgeon, however long he may 
have practiced the art: for, in many cases, he cannot 
know what operation ought to be performed, or how it 
can best be effected, while, in other cases, he will operate 
where no operation is required. Even in the most pure- 
ly mechanical arts, the hand is greatly aided by an intel- 
ligent head : and the value of scientific knowledge, in 
such arts, is shown by the fact that many important im- 
provements have been made in them by men of science, 
who were not operative artisans at all, after the empirics 
had long employed the old method, without ever dream- 
ing of a better.(31) 

Among the intellectual arts, Rhetoric has long held a 
conspicuous place. The Greeks applied it mostly to pub- 
lic speaking, : but it is equally applicable to all didactic 
discourse. It is based chiefly on Psychology, Logic and 
Philology ; and it discusses all discourse which is design- 
ed to produce conviction, whether this be the sole im- 
mediate object or not. It differs essentially from the 
emotional arts, in regarding emotion only as a means 
of securing conviction, and influencing the conduct of 
those addressed. Grammar treats of style only so far 
as literal accuracy is concerned, while Rhetoric consid- 
ers also those qualities of style which affect the judge- 
ment and the feelings. As its principles are drawn 
from other departments, and it is chiefly occupied with 
the means of effecting a particular end, Rhetoric is prop- 
erly classed with the intellectual arts, although some 
have ranked it as a science. 

A person's future condition often depends on his being 



Sec. 3.] Technology. 395 

convinced of a certain truth, which, if believed, will pow- 
erfully affect both his feelings and his conduct. But he 
rejects it, owing to the advocate's failing to present it in 
a proper manner. Hence the importance of knowing 
the best means of communicating truth, and leading 
those addressed to perform the requirements of duty. 

The art of Education has much in common with Rhet- 
oric, since children possess the same powers and suscep- 
tibilities as adults, although in an immature degree. 
Hence the same rules are applicable, when modified to 
suit the particular condition of those addressed. But 
here the field is much wider, since the object is, not 
merely to instruct, but also to train and develop the fac- 
ulties in a proper manner. The comparatively volatile 
and negligent character of the young, also, renders it nec- 
essary to employ measures which are not requisite in the 
case of adults, in order to secure proper attention, with- 
out which little real progress can be made either in train- 
ing or instructing. 

The subject of education cannot be overestimated, as 
it forms the moral character, and exerts a very extensive 
influence on the physical and intellectual. It properly 
includes, however, the instructions and examples of all 
with whom the young have intercourse, whether pro- 
fessed teachers, parents or associates. 

A knowledge of this subject is useful to parents and 
guardians, as well as to ordinary teachers, on several ac- 
counts. It enables them to perform aright their own 
part in the business of education, in which the parental 
is of more consequence than any other, as its influence is 
most constant and powerful. A parent who is aware of 
the evils resulting from a failure of his duty, in this re- 
spect, and the benefits which flow from a contrary course, 
will confer permanent good on his offspring, of which 
those who are ignorant on the subject have no concep- 
tion. Such knowledge also enables parents to select the 
best accessible teachers for their children, whereas igno- 
rance often hands them over to educational quacks, who 
profess and promise whatever will increase their notori- 
ety and gains, the sole objects of their labors. Thus it 
has sometimes happened that children who were badly 
educated at home, were consigned to worse teachers 
abroad : and when they afterwards followed evil ways, 
the disciples of darkness held them up as a striking proof 



396 Particular Knowledge. [Chap. XXVI. 

of the uselessness of education. Yet such results do not 
in the least disprove the great truth that a good educa- 
tion (not any kind of education) secures right conduct 
in after life. 



CHAPTER XXVI. 

OF PARTICULAR KNOWLEDGE. 

§ 1. Of History. — Foundations and character of History.-— Its Uses. 

— Cautions. — Empiricisms. — Inductions. — Limits of History. — 
Philosophy. — Prophecy. — Causes and Effects. — Selection of Events. 

— Best Historian. — First Merit of History. — Frequent Errors. — 
Two Classes of Historians. — Principal original Authorities. — Cau- 
tion. — Common Defect. — Observations on Study. — Traditional 
Narratives. 

History is founded on personal observation, the testi- 
mony of others, and documents relating to the events re- 
corded. The character of its statements is to be ascer- 
tained by the ordinary criterions of testimony, as if we 
were inquiring into the truth of a narrative regarding a 
recent occurrence, in our own neighbourhood. As the 
events recorded are neither necessary nor general, its 
truths are all contingent and particular. 

History not only gratifies a natural curiosity regarding 
the actions of mankind, and thus affords a refined pleas- 
ure, to persons of all ages, but it also furnishes materials 
for various sciences' and arts : for what has happened, in 
certain circumstances, must always happen where the de- 
termining agencies are the same, although there be sev- 
eral minor differences. Hence we can often determine 
the results of certain agencies, before they have become 
matters of History. Here we also learn various lessons 
regarding the influence of particular institutions, princi- 
ples, and opinions : we are aided in ascertaining the char- 
acter of man, what circumstances are favorable to the 
due development of his faculties and to national prosper- 
ity, and whence spring public distress and misery ; and 
we are warned to exercise proper caution in our inter- 
course with others. 

Scientific and artistic histories furnish many sugges- 
tions and warnings to those who cultivate the different 
bi-anches, as has been already remarked. 



Sec. 1.] History. 397 

History is likewise a powerful instrument of moral 
discipline and enjoyment. For virtuous feelings are ex- 
cited, strengthened, and gratified by tracing the career 
of the good, while vicious passions are checked by the 
exhibitions which are made of their repulsive nature, and 
the consequences to which, sooner or later, they uniform- 
ly lead. Conception enables us, in a great measure, to 
view the events of History like spectators of the scenes 
and events described, while sympathy with laudable ac- 
tions conveys to us a part of the joy of those who per- 
formed them, and, at the same time, stimulates to emu- 
lation. On the other hand, the indignation excited by a 
vivid contemplation of base or vile actions, strengthens 
our resolutions to beware of them, and pursue a different 
course. Thus the achievements of a great and good man 
become the common inheritance of mankind, while the 
course of a contrary character furnishes a perpetual 
warning. 

In order to secure such advantages, the events must 
be fairly and accurately depicted, and we must beware 
of receiving the partial and distorted narratives of un- 
principled men as faithful delineations. If an historical 
work is not substantially accurate, and does not exhibit 
men and events nearly, if not precisely, as they were, it 
will only mislead and corrupt, instead of enlightening 
and improving. 

Empirical generalizations are properly used in History, 
to render its statements more concise and forcible : but 
we should beware of the fallacy of irrelevant empiricism, 
which abounds in various historical works. 

Inductions have frequently been attempted to be in- 
troduced into History: but they are quite alien to its 
nature and objects: and although the truths of History 
are properly employed in establishing inductions, in those 
branches of knowledge to which they properly belong, 
yet the attempt to introduce them here produces only in- 
congruity, distraction of attention, and error. The duty 
of the historian is confined to relating past occurrences, 
with their immediate causes and effects, so far as these 
can be certainly ascertained, leaving every man to make 
such applications of his narrative as he deems proper. 

With regard to futurity, it evidently lies wholly be- 
yond the province of History; and consequently the his- 
torian wanders altogether out of his way when he spec- 



398 Particular Knowledge. [Chap. XXVI. 

ulates about the future : he has quite as little to do with 
prophecy as with philosophy. 

A knowledge of causes and effects forms one of the 
most important parts of History : but we should beware 
of receiving as true, statements made on this subject, 
where it does not appear that they are anything more 
than conjectural opinions. Fallacies of causation abound 
in many histories ; and actions are often attributed to 
motives which had no effect in their production, while 
their real causes are not set forth. Motives must gener- 
ally be learned from the conduct of the parties, their 
statements being frequently mere pretences, or the re- 
sults of self-deception. The real motives were not un- 
frequently very diffei'ent, even from what the parties 
themselves believed: for men wish to stand fair with 
their own consciences, and thus frequently mislead them- 
selves regarding the true character of their motives. 

Remote causes and consequences are not easily traced, 
with any degree of certainty ; and they run to an indefi- 
nite extent. The consideration of them, therefore, forms 
no part of the historian's duty, as it would produce 
doubt and distraction, rather than instruction or enter- 
tainment. 

Actual occurrences are far too numerous to be men- 
tioned in History, while most of them are too trivial or 
unimportant to be worth recording : and few things are 
a better test of an historian's judgement than the mode 
in which he makes his selection. Some weary us with 
commonplace details and gossip, neither interesting nor 
instructive, while the most important parts of the subject 
are either omitted or stated vaguely. Others are equal- 
ly uninviting and uninstructive on account of their ex- 
treme conciseness, and the consequent indefmiteness and 
obscurity of their statements. 

The best historian is he who avoids prolixity, and yet 
sets the events vividly before us, as they really were, so 
that, after reading his narrative, we may have such a no- 
tion of them as if we had actually witnessed them. While 
he totally excludes what is not worth recording, and de- 
votes little space to ordinary occurrences, which we 
could accurately conjecture, he relates all that is requi- 
site to a clear and accurate exhibition of the events and 
incidents, as he seizes and faithfully depicts the charac- 
teristic traits. 



Sec. 1.] History. 399 

The first merit of a history is, truth, without which it 
does not deserve the name. Hence, in selecting works 
for study, those which are scrupulously accurate and im- 
partial, should have a preference over all others. These 
excellences are frequently wanting in histories other- 
wise written with much ability. Some historians exag- 
gerate or distort for the sake of effect ; not a few mis- 
represent from prejudice or malicious motives ; and oth- 
ers frame their statements so as to support their own 
views, theories or secret purj>oses, while many err from 
hurry or carelessness. 

The statements are, in many instances, literally true ; 
and yet they convey a false impression, because some im- 
portant points are omitted, or not related with sufficient 
fullness. Consequently the reader is apt to be misled, 
and to form an erroneous opinion of the people or the oc- 
currences. In other cases, general statements are made, 
which conflict with facts as numerous as those on which 
they are based. Fallacious appeals to the passions are 
not unfrequent, especially in narratives written by parti- 
sans. Opprobrious epithets are freely applied to their 
opponents, while they are equally profuse in commenda- 
tions of their friends, set off by sneers, laudatory maxims, 
or feeble expressions of praise or censure, where truth 
required much stronger language. 

History is vitiated by painting men in colors which are 
either brighter or darker than the reality : for we are 
thus misled regarding the characters delineated and the 
influence of certain agencies on communities. It is dan- 
gerous to believe that mankind are more honest and 
faithful than they really are, while we wrong them, and 
disturb our own peace of mind by attributing to them 
vices of which they are innocent. Nations and individ- 
uals have often suffered severely, owing to misplaced 
confidence, arising from their ignorance of the dark side 
of human nature. On the other hand, the generous and 
benevolent feelings of the mind are deadened, and inter 
course with others is rendered unnecessarily difficult, by 
our being led to believe that all mankind are knaves and 
liars. Hence the propriety of selecting those historians 
who neither blacken nor whitewash, but represent both 
the lights and the shades precisely as they were. 

Historians may be divided into two great classes — 
original authorities, who record facts never before writ- 



400 Paeticulab Knowledge. [Chap. XXVI. 

ten — and compilers, who draw their materials exclusively 
from previously written narratives or compositions. Not 
unfrequently an author belongs to both classes. 

Of original authorities, some write from hearsay only, 
and others record their personal observations. The for- 
mer are generally entitled to much less credit ; and when 
the events related were remote from their own time, they 
are seldom implicitly reliable. Sometimes it is difficult 
to determine to which head a statement belongs ; and, 
in such cases, we must be gttided by a knowledge of the 
author's character and circumstances. 

Among original authorities, the narratives of personal 
witnesses, public records, statutes, treaties, inscriptions, 
official documents, and information derived immediately 
from eyewitnesses, are generally the best. But many 
of these are by no means unexceptionable ; and it some- 
times happens that a compilation is more accurate than 
any single authority from which it is composed. 

In Ancient History, it is requisite to ascertain the gen- 
uineness of the composition, as several are spurious ; and 
the same remark applies to some modern narratives also. 

Several narratives relate chiefly military and political 
transactions, while they profess to give the entire history 
of the country. Wars are always effects of certain opin- 
ions : and unless these are delineated, a military history 
is like a picture of a battle-field, which exhibits chiefly 
fury and carnage. No history of a nation or community 
deserves that title, unless it gives a view of the progress 
and changes of religious opinions, morals, law, science, 
art, literature, and domestic life and manners. These are 
the most important subjects of History ; and an accurate 
delineation of them forms the best exhibition of a na- 
tion's real state and progress. 

In studying History, we should first obtain a general 
view of the whole course of events, from the earliest 
times, including the rise and fall of states, the intercourse 
of one country with another, and the general condition 
of mankind, during the various periods. This may be 
acquired from a good set of historical charts, and cor- 
responding outlines. We can afterwards study to ad- 
vantage the history of any particular country, which we 
cannot well do till we learn the outlines of General His- 
tory. 

The most advisable course then is, to take the best ac- 



Sec. 1.] History. 401 

cessible general compilation, as a text-book, and to read 
and compare original narratives and documents as the 
'importance of the particular subjects or periods, and our 
circumstances, require or admit. Original narratives 
generally cover only a small portion of a nation's his- 
tory ; and, therefore, it is desirable to have a good com- 
pilation as a general guide. Yet the former are usually 
more full and graphic, and frequently more accurate in 
details. 

After acquiring the outlines of General History, and 
a good knowledge of the events of Holy Writ, our own 
country should engage our attention, unless our circum- 
stances permit, and our tastes lead, us to study the his- 
tory of the principal nations of ancient and modern times. 
In that case, it is best to follow the course of events, be- 
ginning with the earliest, and coming down gradually to 
the present day. 

Where we cannot study the history of every cele- 
brated nation, we should select those which are most in- 
teresting, either on account of the mental development 
and general intelligence of the people, or of its connec- 
tion with our own. 

Before commencing the study of an author, we should 
ascertain his relation to the facts he professes to relate, 
and the nature of the testimony on which his statements 
are based. This will sometimes cause a little delay and 
additional labor : but these are well repaid, by the checks 
which they furnish against receiving erroneous state- 
ments for historical truths, which will frequently be the 
resiilt of neglecting those precautions. 

We should always endeavor to form an accurate and 
lively conception of the events and scenes, so that they 
may be represented to our minds as nearly like the orig- 
inals as possible. For this is requisite, in order to avoid 
erroneous views, and to feel that degree of interest in the 
narrative which is requisite to agreeable or profitable 
study. It is impracticable to secure the principal ad- 
vantages of this study without an accurate conception 
of the events, and of the characters and circumstances 
of the community whose history we peruse. 

In regard to the earliest history of nations, the student 
will readily find that, although it may have long existed 
in a written form, yet it is generally based on traditional 
accounts, without deriving much light from contempora- 



402 Particular Knowledge. [Chap. XXVI. 

ry written narratives. These accounts should neither be 
utterly rejected without examination, nor implicitly re- 
ceived. On the one hand, traditional narratives of re- 
markable events have been sometimes handed down, 
without any material variation, through many genera- 
tions. On the other hand, they are generally liable to 
be greatly corrupted, during their transmission, even 
where they were originally correct ; and, in many in- 
stances, they are totally spurious, being the result of 
knavery and fraud, operating on ignorant credulity. 

It is true that pure fiction cannot be directly imposed 
on mankind for authentic history : yet this may be done 
indirectly ; and the circumstances of the case, compared 
with the character of the tradition, and well authentica- 
ted facts, derived from other sources, will generally ena- 
ble us to ascertain the actual truth. In the absence 
of any corroboration derived from present facts or the 
testimony of History or Philology, traditional narratives 
are seldom entitled to any weight : and where they are 
evidently absurd, or contradicted by authentic evidence, 
they should be unhesitatingly rejected. On the other 
hand, where they derive corroboration from other credi- 
ble sources, and are neither absurd nor at variance with 
known truths, they may be safely adopted as substantial- 
ly true, save that they are very rarely reliable as to num- 
bers, dates, and places. 

§ 2. Of Chronology. — Use of Chronology. — Epochs. — Means of 
determining Dates. 

A knowledge of the time when events occurred is 
necessary in order to understand their progress and con- 
nections : for otherwise they present themselves to our 
memory as a confused and unconnected mass of facts. 
Hence Chronology forms an important auxiliary to the 
right understanding and remembering of History. 

In order to determine the time when the various 
events occurred, some epoch or fixed period is chosen, 
from which they are reckoned, either backward or for- 
ward, and the number of years which intervene between 
it and an event, determines the time of the occurrence. 

Various epochs have been chosen by different nations : 
but as the Christian states have obtained the control of 
the world, and far outstripped the rest of mankind in ev- 
ery important respect, the epoch of our Savior's birth, 






Sec. 3.] Biogkaphy. 403 

or the commencement of the Christian era, which they 
all employ, is now the only one of much consequence. 

The interval between an occurrence and the epoch is 
ascertained either from the direct statements of persons 
who knew, or from public records, or from computing the 
length of the various periods which form the interval, 
from the testimonies of historians, monumental inscrip- 
tions, coins, astronomical phenomena, &c. 

When the interval between two epochs has been as- 
certained, dates reckoned from one can be converted into 
those reckoned from another, by a simple process of ad- 
dition or subtraction. (32) 

§ 3. Of Biography. — Relations of Biography to History. — Its Uses. 
— Its Advantages and Disadvantages, compared with History. — 
Common Faults, and how they may be obviated in Study. — Char- 
acteristics of good Biographies. — Autobiographies. 

Owing to its nature, Biography is much narrower than 
History in its range: but it is more particular in its 
views, and gives a fuller insight into individual charac- 
ter. History gives an account of communities collective- 
ly, while Biography gives an account of the compara- 
tively small number of individuals whose lives present 
something remarkable, and worthy of remembrance. 
The exact line which separates them, is not very clearly 
marked : yet the general distinction is obvious ; and in- 
deed the two cannot properly be amalgamated. Ac- 
counts of occurrences in which individuals alone were 
concerned, and which did not directly affect any com- 
munity or class, are out of place in History ; and narra- 
tives of public transactions are equally irrelevant in Bi- 
ography. A professed history which consists, in reality, 
of a string of biographies, is apt to mislead us, as the 
characters of the individuals whose lives are recorded, 
may have differed widely from that of the community 
with which they were connected. 

Biography so closely resembles History that most of 
the remarks made in the preceding section are equally 
applicable here. Biography, however, states many mi- 
nute particulars which History overlooks ; and thus it 
often enables us to form more definite conceptions than 
the more general statements of History admit ; and it is 
more available in enabling us to ascertain how an indi- 
vidual of a certain character will act, in given circum- 



404 Particular Knowledge. [Chap. XXVI. 

stances. At the same time it is of comparatively little 
use, in enabling us to determine the effects of laws, opin- 
ions and institutions, because individual peculiarities fre- 
quently control or prevent the ordinary results of those 
agencies, which become conspicuous only when we view 
their effects on nations or communities. 

As biographies are generally written by friends or ad- 
mirers, they are still more affected by prejudices than 
histories. The characters and motives of the principal 
personage and his friends are often represented in colors 
too favorable, while those of their opponents or rivals 
suffer proportionally. Hence due allowances should be 
made. Where the biographer is unfriendly, this state 
of things is reversed ; and we should accordingly lighten 
the picture, as the results of proper investigation require. 

Prolixity is a common fault of biographies ; and this 
is not unfrequently carried to such an extent that the 
works are unworthy of general perusal : and they should 
be used only for occasional reference, when we wish to 
learn something interesting which is not found elsewhere, 
or to compare the statements with other authorities. 

A good biography gives a correct and vivid represent- 
ation of the life and character of its object, of the vari- 
ous agencies that directly influenced him, and of the im- 
mediate effects of his words or actions upon others. It 
avoids the extremes of adulation and detraction, dull pro- 
lixity and vague generalities. 

In reading autobiographies, we should guard particu- 
larly against paralogisms of testimony : for the writers 
often impose on themselves unconsciously, and conse- 
quently are very apt to mislead others. A man is oft- 
en greatly mistaken in his estimate of his own charac^ 
ter, opinions, motives and conduct : and, therefore, if he 
writes his own life, the work will be very apt to abound 
with errors, of many of which he may have no concep- 
tion or suspicion. 



Sec. 1.] General Observations. 405 



CHAPTER XXVII. 

OP THE KNOWLEDGE OF FUTURITY. 

§ 1. Of the Knowledge of Futurity in general. — Common De- 
sires regarding the Future. — Why not gratified. — Future Things 
which can be known, and advantages of knowing them. — Proba- 
bility often sufficient. 

A knowledge of the past is of no value except as it 
affects the present or the future : and as the present mo- 
ment is incessantly running into the past, while the fu- 
ture will never terminate, some knowledge regarding it 
is both important and desirable. Although such knowl- 
edge is narrower than what we may acquire regarding 
the past, yet it may be so extensive as to furnish no rea- 
son to regret its smaller extent. 

The anxiety of mankind to know the principal events 
of their future lives, appears from the general and long- 
continued prevalence of many superstitious arts, which 
professed to accomplish this purpose, but which are only 
delusions, resulting from thoughtless credulity, prejudice 
and knavery, as appears both from experience and rea- 
son. The Most High has wisely and graciously covered 
the particular events of our future lives with an impene- 
trable veil. If evil awaits us which we cannot obviate, 
it is enough when it comes ; and if we receive some un- 
expected good, it is the more agreeable for not having 
been anticipated. 

While some things are thus concealed, and all attempts 
to foreknow them are fruitless, there are many future 
events that we may foresee, and which it is of the utmost 
consequence that we should. The farmer must know 
that summer and winter will return ; otherwise he would 
not be justified in toiling long and hard, and incurring 
great expense, to prepare and sow his fields: and we 
must know how persons of a certain character generally 
act, when placed in given circumstances ; otherwise we 
could not safely trust others with property, or employ 
them to perform important business. So it is always of 
great importance that we should know the general re- 



406 Knowledge of Futurity. [Chap. XXVII. 

suits of certain lines of conduct ; otherwise we should be 
strongly disposed to follow that course which is most 
agreeable at the present time, without paying any proper 
regard to the distant future. And indeed this is one of 
the most common and fatal errors that men ever commit. 

If all the unprincipled persons in the world would em- 
ploy the means within their reach, to discover the cer- 
tain and unavoidable results of their present conduct, 
they would see a picture which would tend very power- 
fully to lead them into better courses. And if many pa- 
rents would examine into the inevitable results of the 
evil training which they give their children, and the good 
effects of a proper course, they would discard the former 
and adopt the latter. But a foolish curiosity to know 
particular future events, has frequently been combined 
with a supine indifference regarding the individual's fu- 
ture destiny. 

In many cases, certainty regarding the future is unat- 
tainable ; but we can arrive at a high degree of proba- 
bility, by reasoning from the circumstances of the case, 
the effects of agencies known to be operative, or present 
signs of futurity : and, in all cases of this kind, probabil- 
ity suffices, for practical purposes. Thus, in regard to 
the way in which individuals will act, in given circum- 
stances, we are sometimes disappointed : but if we use 
due caution, such disappointments will be very rare. So, 
although nothing is more uncertain than the life of an 
individual, yet the average duration of human life, in a 
large community, varies little, from year to year. Even 
the variations caused by a change in the determining- 
agencies, such as famines or pestilences, can generally 
be predicted with considerable accuracy. 

§ 2. Sources of our Knowledge of Futurity. — Necessary and 
Hypothetical Truths independent of Time. — Two Classes of Con- 
tingent Truths. — Source of our Knowledge of the future Perma- 
nence of Natural Laws. — Proofs that the Termination of the pres- 
ent Course of Nature is very remote. — (1) Astronomical Argu- 
ment. — (2) Geological Argument. — (3) Historical Argument. — 
(4) Argument from Prophecy. — Inferences. — Means of knowing 
particular future Events. — Presentiments. — Extent of our Knowl- 
edge of Futurity. — Erroneous Dogma. 

Necessary and hypothetical truths are, from their very 
nature, independent of time and place, and, therefore, as 
true for the past and future as for the present. The 



Sec. 2.] Its Sources. 407 

propositions of Mathematics, for instance, will be as true 
at any future time as they are to-day; and if a certain 
consequence is necessarily implied in a supposition now, 
it will be equally implied forever. 

With respect to contingent truths, the case is different. 
These consist of two classes, general and particular. The 
former comprises most of scientific cognitions, exclusive 
of those of Mathematics, which are all necessary truths. 
The latter express only particular occurrences, and there- 
fore apply neither to previous nor to subsequent times. 
When we say — "Alexander the Great conquered the 
Persian Empire," we express only a particular event, 
which will never occur again : but when we say — " all 
vertebrate animals possess a brain," we express a truth 
which held true in past times, and will do so, as long as 
the present system of the world is upheld. So, the law 
of gravitation, and the properties of heat, light, and elec- 
tricity, are equally permanent ; and the structure of ev- 
ery species of organic beings will be what it now is, as 
long as the species exists. 

A knowledge of the operation of a constant and un- 
changing agent informs us of its future effects, when we 
have learned what they are in one case: and thus we 
know an indefinite number of future truths, including the 
greater portion of all general contingent truths. We 
know that the laws of nature will be the same hereafter 
as they are now, because the same agencies will operate, 
and in the same circumstances. Nothing short of a mi- 
raculous operation of the Deity would alter those agen- 
cies or circumstances : and we know that he will not so 
interfere. Temporary miraculous interference may pos- 
sibly take place, for special purposes : but the supposi- 
tion that this will extend to a permanent alteration of 
the laws of nature, is absurd, since these are the results 
of boundless benevolence, unlimited power, and omnis- 
cient wisdom ; and, therefore, they admit of no improve- 
ment. 

The laws of inorganic nature have been unchangeable, 
so far as we can trace them : and although many old 
species of organic beings have disappeared, and others 
succeeded in their places, no species was ever altered, so 
far as we can find. Now as the same Eternal and Im- 
mutable Creator, who takes no second thought, and all 
whose works are perfect of their kind, will forever con- 



408 Knowledge op Futurity. [Chap. XXVII. 

tinue to rule nature, we must conclude that there will he 
no change of the natural laws, either of matter or of 
mind, at least until the system shall be dissolved by some 
great upbrealring, to be followed by another, and proba- 
bly similar, system. 

That the present system of the world will continue as 
we now behold it, for an immensely long period, may be 
proved by various arguments, of which the following are 
the principal. 

1. Astronomers have shown that the solar system 
would go on forever, as it now does, if there were no re- 
sisting medium, and God did not interfere miraculously. 
The resisting medium, however, appears to exist : but 
there are proofs that its influence on the planets will 
produce no important change, for many millions of years. 
It is further found that the Sun revolves round some dis- 
tant center, at a rate which will require a very long series 
of ages to perform a single revolution. 

Astronomy, therefore, leads to the conclusion that the 
Earth and the other planets will continue to move, and 
receive light and heat from the Sun, as they now do, for 
many millions of years. The immense magnitude of the 
Sun, and the extensive chemical and electric action which 
must be incessantly occurring among its elements, ob- 
viate any fears of its heat or light failing, during all that 
period : and the effect of the resisting medium may pos- 
sibly be, to move the planets very slowly nearer the Sun, 
as these gradually diminish, so as to counterbalance the 
deficiency, until the time of the final catastrophe has ar- 
rived. 

2. Geology shows that the Earth has been the resi- 
dence of animals incomparably inferior to man, for count- 
less ages before he existed : and it is a manifest absurd- 
ity to suppose that it was to be miraculously destroyed, 
a few thousand years after it became gradually fitted 
to be his abode, while it continued to be as suitable as 
ever for his residence. 

3. The preceding argument is corroborated by observ- 
ing the gradual improvement of mankind, from early 
times, and the absurdity of supposing that the Earth 
should be destroyed when they had become enlightened 
and happy, instead of being the reverse, as they were in 
early times. When we closely observe the condition of 
those nations who stood highest, since the dawn of His- 



Sec. 2.] Its Sources. 409 

tory, during the successive periods, there is a marked 
advance, at every step, since those times when the most 
enlightened nations offered human sacrifices, and formal- 
ly worshiped such revolting characters as Moloch and 
Jupiter. The nature of truth and error, and the charac- 
ter of the Most High, who favors the advancement of 
knowledge and virtue, imply that the course of improve- 
ment will be progressive, until mankind shall have be- 
come what they were designed to be, and the future shall 
vastly excel the present. 

4. If we consult the prophecies of Revelation, we are 
led to the same conclusion. There he who foresees the 
end from the beginning, foretells a time when wars will 
cease, knowledge be universally diffused, and all men be 
truly religious, moral and happy.* Although we are not 
distinctly told when this state of things will begin, or 
how long it will last, it is clearly implied that the time 
of its continuance will be very long. Thus, the time dur- 
ing which the pagans were to continue in ignorance, is 
called a moment ; and it is added that they should be 
visited with great mercies, and everlasting salvation. So 
it is said that the glorious time predicted would shortly 
arrive, whence it follows that the interval is of no account, 
compared with the time of its continuance. Now when 
it is observed that this interval extends over some thou- 
sands of years, we must infer, not only that the future of 
man's history will be brighter than the past, but that it 
will be incomparably longer. 

Thus we are led, by different lines of argument, to the 
conclusion that what is science now, will continue to be 
so, for a vast period of time. The Almighty has endless 
duration before him : and he has planned the present ar- 
rangements of the universe on as great a scale with re- 
spect to their continuance, as they are in regard to their 
extent. 

Besides the statements just adverted to, Prophecy fore- 
tells various particular events, of the utmost consequence. 
Of these the general judgement of all mankind, to be fol- 
lowed by a state of endless weal or endless woe, is con- 
spicuous for its paramount importance, and forms a sub- 
ject which every one should examine with a correspond- 
ing degree of attention and care. 

* Isaiah, Chapter ii., 1-4 ; xi., 1-9 ; xxxv., liv. ; Jeremiah, xxxi., 
31-34 ; Micah, iv., 1-4 ; Eevelation of John, xxi., xxii., 1-6. 

S 



410 Knowledge op Futueity. [Chap. XXVII. 

Particular future events may be frequently foreseen by 
knowing that causes operate which will certainly pro- 
duce them, or by observing present indications of them. 
But many cases of this kind contain some uncertain ele- 
ments, which take away certainty, and render the future 
only highly probable. The degree of probability may 
be determined by means of the principles already stated ; 
and it will often be found to be so high that we may 
safely act upon it as if it were a certainty. 

With regard to presentiments, or pretended previous 
knowledge of future events, based on something unde- 
fined, they are nothing but probable inferences from pres- 
ent indications or feelings, which are drawn so rapidly 
and easily that the process is overlooked or forgotten, as 
is habitually done in the case of other guesses. These 
frequently turn out to be correct ; and such instances are 
then noted, and adduced as proofs of the truth of pre- 
sentiments. In the equally, and possibly much more, 
numerous class of cases in which they turn out to be 
false, they are either overlooked or ridiculed. They are 
not essentially different from the conjectures which we 
are incessantly forming regarding futurity, with a dis- 
tinct discernment of their nature. The only difference 
of any consequence is, that presentiments are generally 
less reliable, because they are more frequently based on 
delusive indications, such as dreams, reveries or omens. 

A review of the nature and extent of our knowledge 
of futurity shows that it is adequate to our wants, while 
it falsifies the dogma that knowledge may be dangerous. 
God never does anything which he desires to conceal. 
On the contrary, he desires that we should acquaint our- 
selves with his works, all of which exhibit the high and 
attractive attributes of his character ; and none but those 
who read them aright, fulfil the great end of their being. 
What God does desire to conceal, there is not the least 
danger that any human effort will ever unfold. 



PART V. 

OF THE RETENTION OF KNOWLEDGE. 



CHAPTER XXVIII. 

OF THE RETENTION OF KNOWLEDGE BY SIMPLE EEMEM- 
BKANCE. 

§ 1. General Laws and Rules of Remembrance. — Proper appli- 
cation of remembrance. — (1) Law of Attention. — How Attention 
maybe excited. — Three Rules regarding it. — Pernicious Error, and 
how it may be avoided. — Why an Adept often remembers better 
than a Tyro. — (2) Law of Comprehension. — Importance of Appre- 
hensions. — (3) Law of Generalization. — (4) Law of repeated Ex- 
aminations and Reviews. — Requisites. — When mental Reviews 
preferable to Apprehensional. — (5) Law of Intervals. — Important 
Aids. — (6) Law of Re-comprehension. — Its Applications. — (7) Law 
of System and Arrangement. — Why leading Principles should be 
first attended to. — Advantages of proper Classification. — Principles 
of Arrangement. — (8) Hygienic Law. — Agencies which injure the 
Memory. — Why it is particularly affected by Dissipation. — Practi- 
cal Inference. — (9) Law of the Relation of Thoughts. — (10) Law of 
Recollection. — Where it applies, and how its Application may be 
facilitated. 

The power of remembrance varies greatly in different 
persons, independently of culture : but the power of re- 
membering permanently, vividly, and without confusion, 
depends greatly on the way in which the faculty is ap- 
plied; and we shall consider how this may be clone to 
the best advantage. 

1. The influence of attention on remembrance is so 
striking that it has been noticed from the earliest times. 
Things which we have seen or heard, are generally soon 
forgotten, if they excited little attention ; and whatever 
excites strong attention, is generally remembered perma- 
nently. This holds true of such things as excite strong 
emotion, since these powerfully attract attention. A 
scene of overwhelming grief or ecstatic joy, for instance, 
is rarely forgotten. We may therefore lay it down as a 
law of remembrance, that whatever strongly excites the at- 
tention is generally remembered, and whatever excites lit- 
tle or no attention is generally forgotten. It is owing 
chiefly to the various directions of attention that several 
persons, who haA'e all witnessed the very same scenes, 
remember different things ; every one remembers what 
forcibly excited his attention, and forgets the rest. 



414 Retention by Remembeance. [Chap. XXYIII. 

In order to excite attention, one or other of two things 
is necessary, (l) The subject must spontaneously excite 
a strong curiosity, without any effort on our parts, as 
happens when we view a thing that appears very strange 
and striking, or read a very remarkable and affecting 
narrative. (2) If it be not intrinsically interesting, it 
must appear to have a bearing on something which we 
highly value, and forgetfulness or ignorance on the sub- 
ject must be thought to involve serious consequences. 
These facts suggest the three following rules : 

(1) Endeavor to obtain a knowledge of the elements of 
a subject, and fix them firmly in the memory, during the 
first study : for then it possesses the charm of novelty, 
which is favorable to close attention. If we follow a 
different course, and skim over the surface at first, it be- 
comes more difficult to remember the subject afterwards, 
since the attention is much more apt to wander from the 
point under consideration. 

(2) If the subject p>ossesses no intrinsic novelty, we 
shoidd carefully examine its bearings, until ice clearly 
see its importance, and its connection icith the future. 
"When we distinctly perceive that much depends on our 
understanding and remembering a subject, there is little 
danger that the attention will flag, however uninviting it 
may be in itself. This is proved by the alacrity with 
which mankind do many things, much more disagree- 
able than to study attentively any subject which is worth 
studying, solely for the sake of earning a little money, or 
perhaps gratifying some favorite desire. The rewards 
of the explorer of truth are richer and surer ; and, there- 
fore, it is only necessary that he should understand then- 
value, in order to work with attentive eagerness in the 
pursuit. 

(3) Overlook trifling details, or irrelevant matter / and 
attend only to what is worth remembering, and capable 
of being remembered permanently . For the attention is 
distracted, and remembrance consequently weakened, by 
being drawn to many objects simultaneously. We should 
guard against the pernicious error of burdening and con- 
fusing the Memory by attending to many things at once, 
or by cramming it with a multitude of facts which are 
not worth remembering, or which are sure to be speed- 
ily foi'gotten. The cognitions embraced in all depart- 
ments of knowledge are far too numerous to be retained 



Sec. 1.] General Laws and Rules. 415 

by any Memory ; and there are many truths the recol- 
lection of which tends rather to perplex and mislead the 
Judgement than to answer any good purpose. The con- 
sideration of them leads us to confound matters of no 
consequence with what is material, and to withdraw the 
attention from the essential parts of the subject. 

In order to avoid such results, we should beware of 
paying any attention to things which were better over- 
looked, for the time being, and of attempting to commit 
to memory what is not worth remembering, or what can- 
not be remembered for any length of time. "Where some 
important object caUs our attention to anything of this 
kind, we should pay no more attention to it than the ob- 
ject requires. 

We may now understand why a person already famil- 
iar with a subject remembers new discoveries regarding 
it so much better than others. His previous knowledge 
excites strong attention, on account of the interest he 
feels in it, while it guides his attention to those things 
that are most important. Hence, when we have once 
mastered the elements of a science, our future attain- 
ments in it are acquired and retained with unusual fa- 
cility. 

2. Memory is aided by clearness and distinctness of 
the original comprehensions. As ideas are copies of their 
prototypes, any obscurity or vagueness in the latter nec- 
essarily attaches to the former, and leads to confusion 
and forgetfulness. Hence clearness and distinctness of 
comprehension are favorable to lasting remembrance. 
Thus close attention to comprehensions aids remem- 
brance as well as a right understanding of the subject at 
first. 

As we can seldom form, from mere descriptions, con- 
ceptions so vivid as our own comprehensions of the ob- 
jects, Memory is aided by subjecting to our apprehension 
either the very things to be remembered or accurate rep- 
resentations of them. Thus, we can remember a scene 
which Ave have witnessed much better than one of which 
we merely read a description ; and we remember the po- 
sitions of objects in a country much better by surveying 
a map of it, than by simply reading a description of those 
positions. 

3. As a general proposition includes many particular 
ones, and yet is remembered as easily as one of the lat- 



416 Retention by Remembrance. [Chap. XXVIII. 

ter, Memory is aided by the extension of generalization. 
As inductions are wider than empiricisms, and at the 
same time more free from details, they assist memory as 
much as they extend knowledge; and this is probably 
one reason why mankind have been so prone, in all ages, 
to assume mere empiricisms for scientific generaliza- 
tions. 

4. Remembrance is rendered more distinct and perma- 
nent by repeated examinations and reviews. This truth 
is learned at a very early period of life ; and the practice 
which it suggests is one of the most common means of 
committing to memory jfieces of composition. Yet the 
value of mere repetition is generally overestimated. In 
order to render it effectual, it must be done deliberately 
and attentively: otherwise the whole is apt to be soon 
forgotten, as when we learn a string of words in an un- 
known language. It is further observable that a close 
mental review of a subject, soon after the original com- 
prehension, without appealing to any external object ex- 
cept when the Memory is at fault, generally aids perma- 
nent remembrance more than a re-apprehending of the 
objects. Thus, we remember the contents of a book 
much better by reviewing it mentally after perusal, and 
referring to the book only when we are at a loss, than if 
we were simply to read it over a second time. 

The cause of this is probably the greater degree of at- 
tention required to recollect than to re-apprehend an ob- 
ject. In the latter case the mind may be, in a great 
measure, passive, and wander incessantly to other mat- 
ters, whereas, in the former, it is necessarily active and 
attentive ; otherwise the process could not be performed. 
But where a long time has elajDsed since the original com- 
prehension, the case may be otherwise, as the ideas may 
then have become indistinct, or been wholly lost. 

5. A thing is committed to memory more easily by re- 
peating and reviewing at short intervals, than by the 
same number of exertions, at long intervals. In the lat- 
ter case, one impression is, in a great measure, lost be- 
fore another succeeds, whereas, in the former case, the 
succeeding impression seems to strengthen the former; 
and if the process is properly repeated several times, it 
may produce permanent remembrance, while the same 
number of operations, repeated at long intervals, might 
wholly fail to do so. 



Sec. 1.] General Laws and Rules. 417 

When a subject is so extensive that frequent reviews 
of it are impracticable, we may draw up summaries of 
the most important parts, showing their relations to each 
other, and confine our reviews to these. In such cases 
abridgements and tabular synopses are of great use, as 
well as conversations on the subject with persons who 
know it well, or feel much interested in it. 

6. Fading similitudes are rendered precise and vivid 
by re-comprehending their prototypes. Thus, if we at- 
tempt to recall the idea of a friend, whom we have not 
seen for many years, we may find that it is vague and in- 
distinct : but if he come in sight, we may possibly recog- 
nize the smallest peculiarity in his appearance, the idea 
being now rendered very clear and accurate. Although 
this effect is partly temporary, it is by no means wholly 
so : for the idea continues permanently more distinct and 
vivid than before, especially if we have viewed the pro- 
totype with close attention. By a proper application of 
this principle, the attainments of early life may be, in a 
great measure, preserved through all our later years. 

7. Memory is aided by a systematic course of learn- 
ing, and a proper arrangement of our acquisitions. In 
all subjects, there is a certain relation between one part 
and another, which may be made subservient to the re- 
membrance of both. In order to this, we have only to 
trace and attentively mark these relations ; and then the 
idea of the one will recall that of the other. But this 
will not generally happen, unless we examine the vari- 
ous parts of a subject, in regular succession, according to 
their relations : for if we pursue a different course, the 
ideas of the various parts w T ill be confused in our minds, 
and the connecting bond will be wanting. 

The remembrance of a leading principle will generally 
secure that of its subordinate truths or consequences, 
provided we first learn the former, then proceed to the 
latter, and mark the relations in which they stand to 
each other. A proper system of classification will ena- 
ble us to do this with little difficulty, as it renders the 
relations of the various parts to each other easy to be 
discovered. 

In arranging our acquisitions we should be guided by 
the ordinary principles of classification, already discuss- 
ed ; and when we have once made an arrangement, on 
particular principles, we should not change it afterwards, 

S 2 



418 Retention by Remembrance. [Chap. XXVIII. 

unless for some urgent reason, as the change confuses the 
Memory. 

8. The Memory is much influenced by the state of the 
nervous system. This is frequently observable in severe 
injuries of the head, and in several diseases affecting the 
brain. A wound in the head has sometimes led to a per- 
son's forgetting a great part of his language, and much 
of his knowledge of other things. So everything which 
produces a languid or diseased state of the blood, weak- 
ens the Memory, owing to the injurious influence exert- 
ed on the brain. That this is not owing merely to dis- 
tracting the attention, appears from its existing where 
there is no such distraction, although, in many cases, 
this difficulty also is added. 

Dissipated habits affect memory directly by their dele- 
terious influence on the blood, and consequently on the 
brain, while they affect it indirectly by destroying the 
power of close and continued attention. Hence the reg- 
ular and temperate habits which are requisite for gener- 
al vigor of intellect, are equally necessary for faithful and 
permanent remembrance. 

What was formerly said regarding the propriety of 
attending to the laws of health, during investigation, is 
equally applicable to this subject, because every serious 
violation of these laws injures the brain, more or less, 
and thus impairs the power of clear and vivid remem- 
brance. 

9. Certain thoughts are so related to each other that 
thinking one leads us to think the other. This law op- 
erates so incessantly that it can hardly escape the notice 
of anybody ; and, as we have already seen, Memory con- 
sists wholly in the faculty of thus passing from one thought 
to another, whence it appears that direct remembrance is 
loholly dependent on the relations of thoughts. 

10. Recollection is exercised by recalling the thoughts 
to which the one sought is related. It frequently hap- 
pens that, although we have no direct remembrance of 
the thing sought, we know that it is related to some- 
thing which is remembered directly. Thus, we may have 
no direct remembrance of the time when we last saw a 
particular friend ; but we may remember it was at such 
a place ; and we may then directly remember the time 
when Ave were there. So the time may often enable us 
to recollect the place where something happened. 



Sec. 2.] Relations of Thoughts. 419 

In order to facilitate the application of this law, we 
should note to what familiar thought the thing to be rec- 
ollected is related : for by this means the former will be 
apt to be remembered when we are trying to recollect 
the latter. 

§ 2. Op the Relations of Thoughts. — Two kinds of Relations.—- 
Laws of Natural Relation. — (1) Law of Contiguity and Succession. 
— Usual Course of the Similitudes. — Rule based on this Law. — 
Modifications. — How the Relation may be strengthened. — (2) Law 
of Resemblance. — Analogies. — Requisites to render it available. — 
How aided. — (3) Law of Emotions. — Its Operation. — Rule based 
on it. — Advantage attending it. — Important Difference. — (4) LaAV 
of Contraries. — Why less reliable than the preceding. — Arbitrary 
Relations. — Mnemotechny. — Harmony of Laws. — How new Ac- 
quisitions strengthen Remembrance. — Different Effects of Exercise 
on Memory. — Evils of Cramming. — Important Rule. — Means of 
widening the Range of Relations. — Why Sight generally affects us 
more than mere Description. — Disadvantages of visible Representa- 
tions. — Effects of Desires. — Why some things are well remembered 
and others readily forgotten. 

Some thoughts are so related or connected that one 
excites the other without any effort. Thus, the sight of 
one thing leads us to think of another which looks very 
like it ; and when we think of a remarkable scene that 
we witnessed, we think of what occurred. Such connec- 
tions may be termed natural. In other cases, a desire 
to remember a particular thing leads us to search for 
some familiar thought with which we may connect it, by 
a voluntary effort. Thus, if we know when Alexander 
the Great lived, we may remember when the emperor 
Constantine lived, by noting that he was just as long 
after the birth of Christ as Alexander was before it. 
Such relations may be termed arbitrary or artificial, as 
the thoughts attempted to be connected are not natural- 
ly related. 

The following are the principal laws of the natural re- 
lations of thoughts. 

1. The law of contiguity and succession, which may 
be expressed thus : the similitudes of contemporaneous 
thoughts arise simultaneously, and, if not interfered with, 
in the order of their prototypes. If we think, for exam- 
ple, of a certain place which we have lately visited, the 
ideas of the things seen and heard there arise at once, 
with the utmost rapidity, and also the similitudes of all 
our thoughts at that time, so that Ave know what emo- 



420 Retention by Remembrance. [Chap. XXYIII. 

tions we felt, what intellectual processes we performed, 
and what conclusions we deduced. Then the similitudes 
of subsequent thoughts arise, in the order of time, down 
to the present moment, if no volitions or other laws in- 
terfere. But a slight effort of the will may alter, or even 
reverse, the process, and lead us backward, through pre- 
vious thoughts, or some resemblance or contrast between 
something in the series and some other thought, suggest- 
ed either by some external object or by our own feelings, 
may lead the Memory into a totally different channel, so 
that, in the course of a few seconds, our thoughts may 
possibly have roved over the whole creation. 

This law suggests the rule that our thoughts should be 
concentrated on a few objects, where ice desire that the re- 
membrance of them should be clear and permanent. For, 
if we act otherwise, so many similitudes arise afterwards, 
when we think of them, that the mind is apt to be con- 
fused, and led off from the path which we desire that it 
should hold. Hence many studies at one time are unfa- 
vorable to remembrance, independently of the bad effects 
of distracted attention while we are learning. 

The law of antecedent and consequent is only a partic- 
ular case of that of contiguity and succession, these al- 
ways standing to each other in that relation. A special 
modification of this case is that of cause and effect, which 
are always related as antecedent and consequent. An- 
other frequent modification is, the law of premise and in- 
ference, which are always contiguous in thought, although 
they may be separated in expression. 

These relations are strengthened by other agencies, 
such as the suggestions of the Judgement, influenced by 
the desire of securing one object or avoiding another, 
and the easy transition from premise to inference, on ac- 
count of the self-evident connection. Thus, when we 
witness a disastrous effect, the desire of removing it 
leads us to think of the cause, and so recalls anything 
which we may have formerly observed, bearing on this 
point. So, when we witness a powerful cause in opera- 
tion, we are reminded of what we may have formerly ob- 
served regarding the effects of the same or similar agen- 
cies. Hence things connected as cause and effect recall 
each other more readily than mere antecedent and con- 
sequent. In the same way, when we think of premises, 
the infei*ences are apt to come into view, independent- 



Sec. 2.] Relations of Thoughts. 421 

ly of previous reasoning ; and hence these are readily 
brought to remembrance. 

To the same general law belong various other laws, 
which are evidently nothing but modifications of it, such 
as that of means and etid, name and object, whole and 
part, to all of which the remarks made in the preceding 
paragraph are applicable. 

2. The law of resembla?ice, which may be expressed 
thus : one thought recalls similar thoughts. Thus, when 
we see an object which looks veiy like one that is famil- 
iar to us, we immediately think of the latter. So when 
we hear a musical air, like one which we admire, the idea 
of the latter immediately arises ; and if a foreign field ex- 
hales a fragrance like those of our native place, we im- 
mediately think of the latter, and the scenes of child- 
hood. One of the most common exercises of this law is 
in recognition, where the comprehension of the proto- 
type recalls the similitude, as formerly stated, and thus 
we recognize and identify many objects formerly appre- 
hended. Although apprehensions recall ideas more viv- 
idly than similitudes do, yet the connection extends 
equally to all. 

This law extends to analogies, as well as to direct re- 
semblances ; and some of the most important applica- 
tions of it are based on this property, as the success of a 
discoverer or inventor frequently depends on some anal- 
ogy, suggested by what is already well known. 

In order to render the law of resemblance sufficiently 
available, the points of similarity must be perceived; 
and the more numerous these appear, or, in other words, 
the more complete we observe the likeness to be, the 
more readily and surely will the one object recall the 
other. As the closest resemblances are not always ap- 
parent at first sight, the operation of this law will be fa- 
cilitated and extended by our knowing the recondite, as 
well as the manifest, points of similarity between two ob- 
jects ; and hence remembrance is aided by marking the 
former as well as the latter. 

3. The law of emotions, which may be expressed thus : 
things directly connected with powerful emotions, are re- 
called with unusual facility . Let a person, for example, 
attend to his ordinary business, just after hearing of the 
death of a beloved friend : his thoughts may, for the mo- 
ment, be wholly occupied with his business ; but, speed- 



422 Retention by Remembkance. [Chap. XXVIII. 

ily, and without any external cause, he thinks of the 
deceased: again he banishes the painful thought, and 
again it soon intrudes. On the other hand, a person 
who has just heard a very joyful piece of news, ever and 
anon returns to the agreeable theme. 

Owing to the operation of this law, which acts with 
great force and constancy, things which have once ex- 
cited strong emotions are apt to be easily recalled ever 
afterwards, independently of the greater degree of atten- 
tion which they may have excited in the first instance. 
Hence we should, if possible, place those things which ice 
desire to remember, in such a light that they will poicer- 
fully affect our sensibilities. If we do so, there is little 
danger that they will be afterwards forgotten. 

A great advantage attending the operation of this law 
is, that those subjects which are most important excite 
the deepest emotions, when things are well understood 
and seen in their true bearings. The strong emotions 
requisite to permanent remembrance are by no means 
unfavorable to the acquisition of truth : for they rather 
secure than distract attention, and generally become 
strongest after the investigation has been concluded, as 
the very uncertainty of a proposition tends to moderate 
emotion, until its real nature has been ascertained. 

Those violent and transient emotions termed passions, 
differ widely from the deep and permanent feelings which 
arise from taking a calm and extensive survey of an im- 
portant subject. The former always spring from exag- 
gerated, narrow, or one-sided views of a subject; and 
they are liable to occur only when we consider a subject 
of real or supposed importance, which we have never 
rightly understood or seen in its true light. They are 
decidedly unfavorable to the acquisition or retention of 
truth, since their violence concentrates the attention too 
much on certain points, and thus leads to others being- 
viewed hastily or altogether overlooked. But those pei - - 
manent emotions are not so violent as to produce any 
such results ; and they generally arise from views essen- 
tially correct. 

4. The law of contraries, according to which thinking 
of a thing recalls its contrary. When we are oppressed 
with the heat of summer, we are reminded of the cold 
of winter ; and when we see a desert waste, we are apt 
to think of a fertile land. Here, however, the connection 



Sec. 2.] Relations of Thoughts. 423 

does not seem to be primary and immediate ; but some 
emotion or sensation suggests its contrary, by some in- 
termediate steps. The uneasy sensation of heat, for ex- 
ample, leads us to desire cold ; and the sight of the des- 
ert leads us to think of the cause of its barrenness, 
whence we pass, by a natural transition, to the fertile 
region. 

Owing to its dependent nature, this law is less con- 
stant and reliable than the others, and of comparatively 
little value in aiding memory. 

Arbitrary relations are frequently useful for temporaiy 
purposes : but they are seldom of much use in aiding 
pei'manent remembrance, as the relation selected is very 
apt to be forgotten. Rules for the formation of such re- 
lations are of no value whatever, since that which first 
offers is generally the best for effecting the temporary 
recollection for which alone these relations are of any 
use, as it is the one which will most readily suggest it- 
self when required. Systems of Mnemotechny are appli- 
cable chiefly to dates and numbers : and even these can 
generally be remembered more effectually by other 
means. 

Those relations which are aided by extraneous sugges- 
tions, like that of cause and effect, or premise and infer- 
ence, are more reliable than such as depend solely upon 
the intrinsic power of relation, since the suggestions co- 
operate in producing the desired result. Hence relations 
based on some real likeness or natural connection of the 
things related, are more effectual than such as depend on 
fancied resemblances or casual juxtaposition ; and, there- 
fore, we should attend chiefly to the former. Thus, a 
public speaker may remember the different parts of his 
discourse much better by giving it a logical form, and 
marking the mutual connection and dependence of its 
several parts, than by attempting to connect them with 
the various rooms of a house, as was frequently done by 
some of the ancient orators. 

In noting resemblances, we should attend primarily to 
the most important, or those which determine the gener- 
al character of the objects, and attend to minor points 
of similarity afterwards, since the former are most easily 
remembered, and suggest the latter. Hence the laws of 
remembrance here harmonize with those of original ac- 
quisition. 



424 Retention by Remembrance. [Chap. XXVIII. 

Since every observed relation of one thing to another 
forms. a connection, remembrance is strengthened as the 
number of such relations increases : and hence, as long 
as new acquisitions multiply such connections, the more 
we know, the better we remember. Such additions to 
our knowledge multiply the bands that unite its various 
parts in the Memory, while they are themselves associ- 
ated with so many of the old elements that they are in 
little danger of being forgotten. A new discovery often 
unites into one whole many elements of knowledge hith- 
erto apparently unconnected. It is thus that Memory is 
apparently strengthened by exercise : for if we merely 
load it with unconnected or unrelated facts, it becomes 
confused and weakened, instead of being strengthened. 
We should, therefore, never attempt to burden it with 
unimportant details, which are not worth remembering. 

In order to strengthen the Memory, toe should mark 
the various relations which the thing to be remembered 
bears to several others that are well known, and avoid un- 
important and unconnected details. By this means it 
will become associated with all these, so that it may be 
recollected by thinking of any of them. Consequently 
the practice of observing the relations of new acquisi- 
tions to our previous attainments, is as favorable to re- 
membrance as it is to discovery and invention. 

A good means of widening the range of known rela- 
tions is, to observe a thing in as many different ways as 
circumstances will permit : for it may thus become asso- 
ciated with the ideas of the different senses ; and if one 
fail or hesitate, the others may still avail. Thus, in the 
case of chemical or mineral specimens, we may see, feel, 
smell and taste the substance whose properties we desire 
to remember. 

Owing to the comparative feebleness of the power of 
Conception, in the great majority of mankind, things ad- 
dressed to the eye produce a more permanent impression 
than mere descriptions : but the narrow limits of ocular 
representations render the latter generally indispensable ; 
and, in many of the most important subjects, the former 
are unavailable, as no accurate representation can be 
given. Thus, the best representations of the solar sys- 
tem are so defective that the notions which they convey 
are extremely erroneous, unless they are corrected by 
the aid of desci'iption and conception, while, in the case 



Sec. 1.] General Observations. 425 

of purely mental objects, such representations are often 
worse than useless. 

Although desires and volitions are incessantly chang- 
ing the previous currents of our thoughts, and. substitu- 
ting others, yet every train of thought strictly obeys the 
laws of relation : and hence these ever-varying currents 
may recall any former act or thought of our lives which 
is connected with others. Things much valued are well 
remembered, not only on account of the attention which 
they excite when they are thought of, but also because 
we voluntarily search for them, and dwell on them when 
they are presented to view, whence they become strong- 
ly connected with many other things. For similar rea- 
sons, things little valued are apt to be totally forgotten, 
except where they have severely pained our feelings. 



CHAPTER XXIX. 

OF THE RETENTION OP KNOWLEDGE BY MEANS OE EX- 
TERNAL SIGNS. 

§ 1. Of External Signs in genekal. — Advantages of External 
Signs.— Various Modes of their Operation. — Monuments and Com- 
memorations. — Advantages and Disadvantages of direct Likeness- 
es, Symbols, and Phonetic Eepresentations. — Best Course. 

The extent of human attainments is such that, after 
employing all the aids of Memory discussed in the pre- 
ceding chapter, external signs are requisite, in order to 
secure the largest and most important portions of knowl- 
edge. For, although similitudes represent the things to 
be remembered, without any external sign, yet they are 
liable to be forgotten ; and as they pass away with the 
individual, they cannot make knowledge permanent in a 
community. 

External signs operate in various ways. When a per- 
son ties a string on his little finger, or a knot on his hand- 
kerchief, the sight of the unusual object recalls its origin, 
evidently in virtue of the law of cause and eflect. Of 
the same kind are monuments and periodic commemora- 
tions. These preserve a knowledge of occurrences, be- 
cause they excite curiosity and inquiries regarding their 
origin, so that every generation learn the cause from their 
predecessors, and afterwards communicate it to those 



426 Retention by External Signs. [Chap. XXIX. 

who succeed. So the boundaries of laud are frequently 
known from posts or stones fixed in the ground. But 
such devices, at the best, preserve only the remembrance 
of the principal facts or events : and, in order to retain a 
knowledge of details, we must have recourse to more va- 
ried and unequivocal signs. 

Direct likenesses possess over all other mnemonic signs 
the advantages of representing the very things to be per- 
petuated, in a lively and striking manner, placing a scene 
before the eye without calling in the aid of Conception, 
and exhibiting some peculiarities which description can- 
not so well convey. They give us more accurate notions, 
in many instances, than can possibly be obtained from 
mere descriptions, while they render similitudes more 
precise and vivid, like re-comprehending their proto- 
types, so that, when very accurate and complete, their 
effects are not much inferior, in these respects, to the lat- 
ter process. 

Symbolic representations are employed chiefly where 
direct likenesses are inadmissible, owing to the thing 
which it is designed to perpetuate being invisible, or in- 
capable of direct pictorial representation : and they some- 
times set this forth more forcibly and comprehensibly 
than verbal descriptions, just as figurative expressions 
sometimes portray an occurrence more clearly and strik- 
ingly than those which are literally true. 

Yet much is still requisite in which those devices 
Avholly fail. Direct likenesses can generally represent 
only a small portion of what is visible, while the invisi- 
ble, which is usually the most important part of the sub- 
ject, cannot be thus represented at all. The range of 
symbolic likenesses, again, is very narrow, unless their 
number is multiplied so as to overburden the Memory, 
and render their import very liable to be misunderstood 
or forgotten. Hence the value of writing or printing, 
which, by means of characters denoting its elementary 
sounds, pei*fectly expresses language, so that we can ac- 
curately and easily retain whatever can be spoken. 

Writing furnishes the means of expressing all human 
thought with great precision and the utmost generality, 
while the number of characters required is so small that 
the Memory need never be burdened in remembering 
them. It also removes the vagueness and uncertainty 
which frequently attach to all other methods, when we 



Sec. 2.] Writing. 427 

attempt to express details, or a continuous chain of 
events or thoughts ; and it prevents the numerous mis- 
takes and total loss of knowledge incident to relying on 
simple remembrance. Moreover, as the composition can 
be rewritten or reprinted without limit, it can be hand- 
ed down unchanged through countless ages. Thus writ- 
ing preserves the knowledge of past ages, and enables 
those of succeeding times to use or improve upon the at- 
tainments of their predecessors. 

As every class of signs possesses advantages and dis- 
advantages, the best method is that which combines the 
advantages of all, as the subject may require. The ex- 
pressiveness and directness of pictures and solid repre- 
sentations may be combined with the brevity and gener- 
ality of symbols, and the simplicity, comprehensiveness, 
ease and exactness of phonetic writing. We are thus 
furnished with the means of retaining all our thoughts 
with force, precision, perspicuity and accuracy, transmit- 
ting them to the most distant parts of the world or re- 
motest posterity, and studying the very words of others 
as deliberately and frequently as we please. 

§ 2. Of the Eetention of Knowledge by Writing. — Eequisites 
to render what is written available. — Things to be attended to, in 
writing for our own use. — How to be secured. — Abstracts. — Copy- 
ing. — Various Courses. — Extracts. — Tables. — Caution. — Defi- 
nitions. 

When we have properly written down anything which 
we wish to remember, all that is requisite, in order to its 
being available afterwards, is, that the writing should be 
preserved, and that we should remember where to find 
it, and what is denoted by the characters and words em- 
ployed. This we can generally do by means of the 
methods discussed in the preceding chapter. 

In writing solely with a view to the retention of knowl- 
edge, all that we require to do, is, to express ourselves 
with perfect clearness and precision. But this is not so 
easily effected as we might suppose. While we distinct- 
ly remember what we have written, Ave may think that 
all our expressions are quite unobjectionable; but they 
may present a different aspect by the time we have for- 
gotten what we wrote. 

In order to determine whether our expressions are 
sufficiently perspicuous and exact, we should view them 



428 Retention by External Signs. [Chap. XXIX. 

like one who knows nothing of the subject, except what 
he derives from the writing ; and a little practice will 
enable us to do so with little difficulty. We shall sel- 
dom err if we write as we should do, in addressing a per- 
son to whom we desired to communicate clearly every- 
thing which is to be remembered, in such a manner that 
there would be no danger of his mistaking or hesitating, 
regarding our meaning. 

When all that we require to remember has been prop- 
erly written already, it will be unnecessary to copy it, 
except where we have not easy and constant access to 
the works in which it is found. But it is frequently ad- 
visable to make an abstract of a treatise, as this will fix 
the attention more closely than mere reading, and lead 
to our obtaining a clearer view of the subject. Mere 
copying is generally of little value, as the process is so 
purely mechanical that we may be thinking more intent- 
ly of something else during the operation. 

Facts which ought to be remembered, and yet are not 
contained in any composition within constant and easy 
reach, may be minuted in a common-place book. We 
may either have several books of this kind, for various 
subjects, or write our entries continuously in one, and, 
when it is full, take another volume. Wherever our 
minutes are voluminous on each of several subjects, it is 
better to adopt the former plan, as the different subjects 
will thus be kept distinct. 

Where we desire to note something in a composition 
to which we have constant access, it will generally be 
sufficient to mark the passage, and give a reference to 
the book and page in a general index. But if the mat- 
ter worth remembering is blended with much that is not, 
a minute in the common-place book may save much time 
when we afterwards come to refer to it. 

In carrying out such plans, young learners are apt to 
collect a good deal of dross, along with valuable matter. 
But experience generally corrects this error, after a few 
years : and those who follow no such plan, will often find 
that they formerly read much which they would like to 
retain permanently, but which has now either gone be- 
yond their reach, or lies they know not where. 

In minuting matters which abound with details, much 
benefit may often be derived from forming synoptical 
tables, which may enable us to take a bird's eye view of 



Sec. 1.] Whiting. 429 

the principal facts, and thus greatly assist remembrance, 
while they facilitate reference. Running the eye repeat- 
edly and attentively over their contents, and then review- 
ing them, will generally fix them in the Memory better 
than all the machinery of Mnemotechny ; and the remem- 
brance of what is thus acquired will greatly aid us in rec- 
ollecting the substance of the whole subject. Such aids, 
however, should be used only as auxiliaries, and by no 
means to the exclusion of regular narratives or exposi- 
tions-: for they necessarily present nothing but a skele- 
ton of leading facts or events, and exclude the most in- 
teresting parts of the subject. 

Wherever we have occasion to use a word regarding 
whose exact meaning we may possibly experience some 
difficulty afterwards, we should either properly define it, 
or refer to some accessible definition which we follow. 
Definitions are required only where a term is unknown, 
obscure, equivocal, or liable to be forgotten, as otherwise 
it can cause us no difficulty. 



CHAPTER XXX. 

OF THE MEANS OF POSSESSING A EEADY COMMAND OF 
OUR KNOWLEDGE. 

§ 1 . Requisites for possessing a ready Command of our Knowl- 
edge. — Importance of this Subject. — Eight Requisites, with Re- 
marks. 

The methods already discussed will generally secure 
knowledge so that it is not lost beyond the power of rec- 
ollection or recall. Many things which never occurred 
to us for years, and which appeared to be completely 
forgotten, are often vividly recalled afterwards, by means 
of some relation or external object. But this degree of 
retention is quite insufficient for many purposes. For if 
we form our decisions, and act, upon partial views of a 
subject, while we overlook or forget important facts, the 
subsequent recollection of these will generally be too 
late. Knowledge forgotten or overlooked when it is 
wanted, is of little avail. The evils arising from this 
source are of frequent occurrence, and, in many cases, 
extremely serious. In order to avoid these, and to have 



430 Command of Knowledge. [Chap. XXX. 

our knowledge sufficiently at our command whenever it 
is needed, the following things are requisite. 

1. The things to be remembered must have been at- 
tentively considered and well understood, when they 
were originally learned, or at least at some former time : 
for we do not well remember what we never rightly 
considered or understood. 

2. They must have been repeatedly reviewed with at- 
tention, and their relations carefully observed, so that 
they are strongly connected with things which we are 
not in danger of overlooking or forgetting. 

3. Our knowledge must be classified and arranged ac- 
cording to its natural connections : otherwise the pre- 
ceding requisite cannot be secured ; for if all our knowl- 
edge lies in a confused mass, it is impossible to discover 
the principal relations, and we must rely chiefly on cas- 
ual associations, which rather lead us astray than guide 
us to what we ought to remember. 

4. We must be systematic in our habits : for if we are 
accustomed to run from one subject to another, entirely 
unconnected with it, then back to the first, and so on, our 
knowledge of them will be so confused that the same 
evils will result which are mentioned in the preceding 
paragraph. 

5. We must cultivate equanimity, and suppress anx- 
ious and violent emotions. These are almost as injuri- 
ous in their influence on memory as they are in the orig- 
inal acquisition of knowledge : for they concentrate the 
attention on other objects than those with which it should 
be occupied ; and hence we cannot call up our knowledge 
when required, whereas, if our minds were calm and un- 
ruffled, the requisite cognitions would readily arise. 

6. We should not attempt to recall our knowledge 
while we are under the influence of strong sensations, 
whether pleasant or painful, for the same reasons as those 
just mentioned. 

1. Attention must be paid to bodily health. Disease 
not only distracts the attention, by the painful sensations 
which accompany it, but it directly affects the Memory 
by its influence on the nervous system. Hence the ad- 
vantage of a close adherence to the laws of health. 

8. Where our knowledge is partly in writing, we must 
have some accurate notion of the nature of what is writ- 
ten, and where it is to be found: otherwise we cannot 
avail ourselves of it when required. 



Sec. 2.] Means of acquieing it. 431 

§ 2. Means of acquiring and employing the preceding requi- 
sites. — Systematic Habits. — When a Change of Plan is desirable. 
— Common Error of Young Persons. — Evils of Hurry. — Difference 
between Reading and Study. — Means of securing Equanimity, and 
moderating Passion. — Proper mode of dealing with Sensations. — 
Power of bad Habits. — Means of securing Health. — Common Er- 
ror regarding Writing. — Means of rendering Writing available. — 
Indexes. — Influence of the Judgement on Memory. 

The modes in which the three first requisites mention- 
ed in the preceding section are to be acquired, have suf- 
ficiently appeared ; and therefore any further considera- 
tion of them is unnecessary. 

In order to secure systematic habits, we must form 
some plan of proceeding, and adhere to it, as closely as 
circumstances will permit. Young persons are apt to 
abandon all system, as soon as they find that the one 
planned cannot be carried out, owing possibly to its be- 
ing too rigid, and too minute in its details. Yet if we 
modify and simplify our original scheme, as exj)erience 
shows to be desirable, we shall find that occasional inter- 
ruptions and deviations will have little influence on the 
benefits derivable from systematic habits. If we find 
that we are frequently interrupted, during the time allot- 
ted to a particular pursuit, we may possibly alter the 
time to advantage. The circumstances of individuals 
differ so much that every one should form his plans to 
suit himself. 

Young persons are apt to err in expecting to accom- 
plish too much within a given time : and they often allot 
a few months to what will require as many years to ef- 
fect properly. To have important results well accom- 
plished, generally requires time : and to hurry through 
our studies and investigations, is a very bad course, be- 
cause we thus generally learn little and that superficially, 
while even that is apt to be mingled with much error, 
and to be mostly forgotten, within a short time. It also 
leads to a habit of careless study and investigation, which 
may cause innumerable errors and misconceptions. Hur- 
ry, and the confusion and oversights that uniformly at- 
tend it, are as injurious to remembrance as they are to 
right understanding ; and therefore we should avoid it, 
with the utmost care. 

We should also guard against the common practice of 
cramming our memories with the mere statements of 
others, without ascertaining either their exact import or 



432 Command of Knowledge. [Chap. XXX. 

their character and bearings. As it is not everything 
which is swallowed that furnishes bodily aliment, but 
only food, which is properly digested and assimilated ; 
so it is not what we read or hear that instructs the mind, 
but only truth, rightly understood and permanently re- 
membered. 

In order to preserve an even tenor of mind, and avoid 
the extremes of stormy passions, and the apathy which 
inevitably succeeds, we should note the blinding effects 
of the former on the intellect, and how completely they 
vitiate every investigation performed while we are under 
their influence or during the succeeding prostration. The 
habit of taking wide and close views of the subject, will 
also conduce greatly to the same result. By taking nar- 
row and one-sided views of a subject, we are very liable 
to work ourselves into a passion about things which are 
easily seen to be quite insignificant, when considered 
closely and from the true point of view. Our feelings 
may be both deep and permanent, without ever rising 
into gusts of passion, which can always be subdued by 
extending our view beyond their exciting objects, or by 
observing these in their true bearings; and habit will 
make this course comparatively easy. 

As to sensations, it is generally easy to abstain from 
important investigations or decisions while we are affect- 
ed by any which materially interferes with attention. 
Every one will see the impropriety of raking the Mem- 
ory, and deciding important questions, while he suffers 
acute pain, and the same objection exists in the case of 
all violent feelings, whether pleasant or painful. Many 
sensations are much influenced by our habits ; and those 
formerly recommended will place the most dangerous of 
this class, such as the appetites, sufficiently under the 
control of the Judgement. 

To secure health, we must know what its conditions 
are, and rigidly observe them : for if we once fall into 
the habit of neglecting them, we are apt to go on from 
bad to worse, one violation leading to a deeper, and the 
strengthening habits rendering a return to better courses 
more and more difficult. People often flatter themselves 
that they can easily abandon a habit when, in fact, they 
do not possess sufficient resolution and energy to do so. 
As a man who floats with the stream knows not the dif- 
ficulty of stemming the current, so the slave of bad habits 
knows not their strength till he has wholly subdued them. 



Sec. 2.] Health — Writing, <fcc. 433 

In ascertaining what are the laws of health, we must 
be guided by the disclosures of science regarding the 
structure and wants of our bodily organization, and the 
influence exerted on it by the various agents within and 
around it. To follow the opinions and practices of the 
ignorant, as good guides, is like adopting the views of a 
cheat as a correct representation of honesty. 

With respect to writing, we must avoid the common 
error of thinking that when once we have a thing writ- 
ten down in manuscript, or in a printed volume, it is 
henceforth at our service, whenever it may be required: 
for it is liable to be overlooked altogether, or we may be 
unable to find it in time, or it may never have been prop- 
erly understood. To obviate such difliculties, we should 
well understand what we read or write, and have mat- 
ters which we require to refer to afterwards, entered in 
an index. We should also occasionally review our ac- 
quisitions, so that we^hall have a correct idea of their 
nature, and neither selfcch for what is not there, nor neg- 
lect what is, when there is occasion for it. If we have 
separate books for different subjects, each should have 
its own index, in which may be entered both what we 
have ourselves written, and what we have read and de- 
sire to note. 

An index should be so constructed that it will enable 
us to find any passage to which it refers, without diffi- 
culty. In order to this, the initial word should be that 
which we are most likely to refer to ; and, where there 
is room for doubt, there should be several, referring to 
the passage, so that we cannot fail to find one or other 
of them, without much trouble. An index can be made 
by ruling a blank book, and writing proper headings, or 
it may be purchased ready made from a stationer. 

In forming a judgement on any important subject, we 
should carefully run over the various parts of it, till we 
have ascertained whether we have distinctly before us 
everything requisite to obtain a correct view of it: and, 
if we have any doubt on this point, we should search and 
think, till it is fairly removed. Such exercises strength- 
en the Memory, by concentrating the attention on partic- 
ular things ; and thus they not only bring up all our 
knowledge on that occasion, but they render it more 
serviceable for future use. 

T 



434 



Tabulae View. [Chap. XXXI. 



CHAPTER XXXI. 



TABULAE VIEW OP THE MEANS OF EETALNIKG KNOWL- 
EDGE. 



Knowledge is retained by means of 

r 



I. Simple Remem- 
brance or Rec- 
ollection, de- 
pendent on 



II. 



External Signs, , 
including 



1. Attention. 

2 . Clearness and distinctness of comprehension. 

3. Extension of generalization. 

4. Repeated examinations and reviews. 

5. System and arrangement. 

6. Soundness of the nervous system. 

7. Relations of thoughts, which are 
(1.) artificial, and 

(2.) natural, including laws of 
(a.) Contiguity and*uccession, 
(6.) Resemblance, 
(c.) Emotions, and 
_ (d.) Contraries. 

1. Commemorative signs. 

2. Likenesses. 

3. Writing and printing, rendered available by 
(1.) Perspicacity and precision of expression, 
(2.) Proper definitions, 

(3.) Abstracts and common-place books, and 
(4.) Tables and indexes. 



NOTES. 



Note 1, Page 13. 
Some have defined Logic as "the science of the laws of thought." 
But this definition is far too wide : for it comprises a great portion 
of Psychology, even if we limit the word "thought" to intellectual 
thought, a limitation not justified by the long "established usage of 
the language. 

Note 2, Page 38. 
The Aristotelians divide a proposition into three parts, the subject, 
the predicate and the copula, or a word connecting the two. Thus, 
in the proposition "man is mortal," is is the copula. I have not 
adopted this division, because it is based on a particular mode of ex- 
pression, different from what is generally used. In ordinary language, 
no copula appears, except where the substantive verb to be is used, in 
some of its forms. 

Note 3, Page 44. 
What is loosely termed a "moral certainty," seems to be nothing 
but such a high degree of probability as will induce belief, in ordinary 
circumstances. The phrase is objectionable, since it leads us to con- 
found certainty with a high degree of probability, things which are 
essentially different. The former does not admit of degrees ; the lat- 
ter does : .the former is wholly unaffected by future discoveries ; the 
latter may be reversed or destroyed by them. 

Note 4, Page 50. 
Reasoning has been frequently defined as a comparison of one thing 
with another, and observing whether they agree or disagree. But 
this definition is very faulty : for it misrepresents the nature of rea- 
soning, and does not express its peculiar characteristic. There is in 
reasoning a comparison of one thing with another ; but this is done in 
order to ascertain whether the one necessarily implies the other, while 
such comparisons as those expressed in the definition are made for a 
different purpose, and form no part of reasoning. Thus, if I look at 
two crows, perched side by side, and see that both are of the same 
color, here is a comparison of one thing with another, and a discern- 
ment of agreement, but no reasoning whatever, since there is no dis- 
cernment of necessary implication or connection. So, if I see a crow 
on a snow-drift, and observe that the former is black and the latter 
white, there is a comparison of two things, and a discernment of dis- 
agreement, but no reasoning. In both cases, there is simply an ap- 
prehension of two things, observed, by means of abstraction, to be 
either like or unlike. On the other hand, when I see the crow before 



436 Notes. 

mc, I know intuitively, and without any discernment of agreement or 
disagreement, that he is nowhere else at that instant. Reasoning is 
an application of Intuition ; and, therefore, where the latter is not 
employed, the former cannot exist. 

Note 5, Page 51. 

The Aristotelians represent reasoning as a comparison of two pre- 
mises, in order to evolve the inference, whereas it consists of compar- 
ing the premise with the inference, in order to ascertain whether the 
latter is necessarily implied in the former. Their view of it is sub- 
stantially the same as that mentioned in the preceding note. Hence 
they represent a syllogism as consisting of four, instead of three, dif- 
ferent parts, two premises, a connective, and an inference, which they 
term the conclusion. They maintain that it embraces three separate 
objects, or notions, two of which are successively compared with the 
third, in the two premises, and then pronounced, in the conclusion, to 
agree or disagree with each other. 

The subject of the conclusion is called the minor, and its predicate, 

the major term : the premise in which the latter occurs is called the 

major, and the other, the minor premise. The subject of the major 

premise, which forms the predicate of the minor, is denominated the 

middle term. Let us take the following syllogism for an example': 

Every man is mortal ; (major premise) 

John is a man : (minor premise) 

Therefore John is mortal, (conclusion) 

Here man is the middle, mortal, the major, and John, the minor 
term. 

This view misrepresents the real process of reasoning in such cases, 
which may be variously expressed as follows : 

(1) John is one of a class individually mortal ; (premise) 
But whatever belongs to a class individually, be- 
longs to every one of that class : (connective) 
Therefore John is mortal. (inference) 

(2) Every proposition which is true universally is true 

of every case included in it : (connective) 

Now it is true universally that every man is mortal ; (premise) 
Therefore the man called John is mortal. (inference) 

The Aristotelian syllogism is unobjectionable only in those instances 
where the major premise is a self-evident truth which shows that the 
minor premise necessarily implies the conclusion, in which cases it 
evidently becomes equivalent to what 1 have termed the connective. 
The two kinds of premise are alike in form ; and they never looked 
any farther: yet they are intrinsically different. Inductive proposi- 
tions cannot form logical connectives, even when they are universally 
true, because they are not self-evident, and much less where they are 
only generally true, as in the instance just given. 

Their vague and erroneous view of reasoning and syllogism have 
led the Aristotelians astray to such an extent that a great part of their 
Logic is worthless, or even worse. "Terms" seem to constitute the 
corner-stone of their fabric, and they evidently attended chiefly to 
expressions, without sufficiently analysing the processes of thought. 
Like their master, they often lost themselves in words, and discussed 
merely different forms of expression, while they professed to unfold 



Notes. 437 

what these denote. The whole machinery of their "moods," "fig- 
ures," and ''rules for reduction," are useless as an intellectual exer- 
cise, and positively detrimental in the actual pursuit of truth, since 
they only cloud and clog the investigator. 

Note 6, Page 54. 

Some affect to doubt whether extension is infinite ; but if they seri- 
ously attempted to determine its boundaries, they would probably think 
otherwise. Boundaries to extension are evidently as impossible as a 
termination to duration. If we think of any part of extension, we 
know there is space all round it ; and if we think of any part of dura- 
tion, we know that part preceded and part succeeds. -Hence the- 
former is infinite, and the latter eternal. 

Another absurd dogma is, that duration and extension are only 
conceptions of the mind, and have no existence beyond it. There is 
nothing more self-evident than that these two things necessarily exist, 
and that they are immutable, and independent of every other thing. 
The dogma probably arose from confounding their nature with the 
faculty by which we discern it, as if one should maintain that the qual- 
ity of hardness exists only in the points of our fingers, because it is 
through these chiefly that we learn its nature. Instead of duration 
and extension existing only in the mind, the latter and every other 
real being exist only in duration and extension. 

Note 7, Page 61. 
The essential nature of change, cause, and power are known intu- 
itively ; and, therefore, the terms expressing them neither require nor 
admit of any real definition, any more than such words as blue, sweet, 
sour, pleasure, pain, &c., but their precise signification is learned by 
simply considering what they are. 

Note 8, Page 61. 
It has been said that the 11th principle is not even true, and much 
less self-evident, for that the Sun attracts the Earth without any me- 
dium. This objection is like declaring that a man may be in two 
places at the same instant, for that we often see ourselves on the north 
side of a room when we are actually on the south side, or that the 
three angles of a triangle are not exactly equal to two right angles ; 
for that, if we actually measure them, we shall always find them either 
a little greater or a little less. That the Sun really attracts or draws 
the Earth, or any other planet, is an absolute impossibility, because it 
has no hold on them, and consequently it can no more draw them 
than it can draw empty space. As action is only a kind of motion, 
the principle is only another form of saying that a being cannot be in 
motion where it is not, which is as evident as that a man cannot be 
where he is not. 

Note 9, Page 71. 

The Aristotelians seem to confound judgements, or conclusions from 

premises, which have been investigated and are believed to be true, 

with propositions, without adverting to the fact that the latter may be 

wholly mental. Some of them seem to have been aware that we 



438 Notes. 

reason in forming judgements, yet to have erred in supposing that 
this is different from ordinary reasoning, and also in thinking that we 
reason whenever we discern the truth of a proposition, which is by no 
means the case. All discernments are known directly, without any 
reasoning whatever. 

Kant's analytic judgements are simply truisms, while his synthetic 
judgements embrace both intuitions and other propositions, so that his 
division only increases confusion. In order to determine the logical 
character of a proposition, we must evidently analyse it, so as to un- 
derstand what it is ; and then, in order to determine whether it is an 
intuition or not, we must compare the subject with the predicate. 
Consequently his analytic judgements are equally synthetic, and con- 
versely, while neither class can properly be termed judgements at all. 
The truth of truisms is discerned precisely like that of other intuitions, 
and the distinctions drawn by Kant are nugatory. Thus we know 
that "a man cannot be in two different places at the same instant," 
just as one knows that " every Englishman is a man." 

Note 10, Page 72. 
One of the most remarkable cases of spectral illusions of which I 
have ever learned, is that related by Dr. E. Patterson in the Edinburgh 
Medicaland SurgicalJournal, for January, 1843. In that instance, a 
man saw the figure of a deceased friend, heard him speak, and also 
felt him pinch his arm. The specter was so distinct that he could 
perceive the color of the clothes : yet he adds that it was dim and im- 
perfect throughout, and that it could not for a moment be considered 
a real object. The illusion regarding his arm, he attributed to cramp 
of the triceps muscle. 

Note 11, Page 77. 
If any person should think that he is immediately conscious of pro- 
ducing the changes consequent on his volitions, I answer that a care- 
ful consideration will show we are conscious of nothing but the voli- 
tion and simultaneous comprehensions. "We are no more conscious 
of moving our arms than we are of inhaling the air which is forced 
into the lungs by the pressure of the atmosphere, when we expand 
the chest. 

Note 12, Page 9S. 

Direct likenesses appear to have been the first signs employed for 
perpetuating knowledge, as they are more obvious and expressive than 
any other ; and some races, like the Aboriginal Americans, never ad- 
vanced beyond this method. It was probably followed by symbolic 
writing, as being the next link in the series. This method has been 
most extensively used by the Chinese, who never went beyond it. 

Phonetic writing was probably invented later than the symbolic, 
because, although the simplest and most complete, it is the least ob- 
vious and most recondite ; yet it is so ancient that its origin and early 
history are, in a great measure, lost in the mists of antiquity. So far 
as we can learn, however, the invention appears to be due to the an- 
cient Egyptians, who certainly practised it at a very remote period. 
Theory would lead us to assume that the earliest writing of this kind 
was syllabic, like the Cherokee alphabet of George Guess, and that of 



Notes. 439 

the Veh people in Africa. But of this there is no clear proof; and 
we find characters representing letters, and not syllables, in the earliest 
extant specimens of phonetic writing. ... 

From Egypt letters passed to the Hebrews, Phoenicians, Assyrians, 
Babylonians, and Indians. The Phoenicians introduced them into 
Greece, whence they spread over Europe; and thence they passed 
into America. 

The first letters were complete pictures of visible objects, the power 
of the letter being the initial sound or articulation of the object's 
name. Thus, an ant, an apple, or an axe might stand for A ; a book, 
a bee, or a box, for B, and so on. Such are the letters found on the 
Egyptian monuments, the hieroglyphics being chiefly inscriptions in 
such letters, often blended with symbolic and pictorial figures. Even 
in several of the Roman characters, the original forms of the objects 
are still apparent. Thus, A was an ox's head, and D, a door, two of 
the angles having been rounded off for convenience of writing ; 
was an eye, T, a cross, and U, a hook. The Hebrew names of the 
letters still indicate the original objects ; for those of the letters just 
mentioned signify ox, door, eye, cross, and hook. 

The primitive literal system was afterwards improved by simplify- 
ing the forms of the letters, and employing only one form to denote 
one power, whereas originally several objects were employed, whose 
names began with the letter. The Greeks perfected the art of writ- 
ing, by expressing all the vowel sounds, which does not appear to have 
been previously done by any nation. It was not till upwards of fif- 
teen hundred years afterwards, that the Syro-Arabian races attempted 
to supply this defect, by the clumsy invention of the vowel points, 
after the old pronunciation had been lost, while the ancient Hindoos 
did not even make the attempt. 

Note 13, Page 107. 

An analysis of the inductive processes shows the futility of the dis- 
tinction that some have drawn between what they term deductive rea- 
soning, syllogism or ratiocination and inductive reasoning or induction. 

We .may also see the absurdity of maintaining that a new kind of 
Logic was invented in the seventeenth century, which they distinguish 
as the Inductive Logic, accompanied with a new method of investiga- 
tion. Induction indicates only the quantitative relation of the pre- 
mises to the conclusion, not the nature of the reasoning by which this 
is established ; and every kind of inductive process was practiced in an- 
cient times. The more rapid progress of knowledge, in modern times, 
has been owing, not to any new method of investigation, but to sev- 
eral other causes, some of which are quite obvious. 

Another similar error is, dividing all reasoning into deductive and 
inductive. The former term is applied to those syllogisms where we 
infer that a particular case of a general proposition is true, provided 
the latter is true ; and, consequently, when valid, it is confined to nec- 
essary truth. By inductive reasoning they understand syllogisms in 
which it is inferred that a general proposition is true, provided every 
particular proposition embraced in it is true, or has been previously 
found to be so, which is evidently nothing but empirical generaliza- 
tion, and which does not, in fact, include any real process of induc- 
tion. Moreover most of our reasonings are quite different from either 



440 Notes. 

of these processes, since both the premises and inferences are particu- 
lar. This is usually the case in the ordinary affairs of life, and very 
frequently in scientific and historical investigations. 

Note 14, Page 128. 

Some authors have attempted to go beyond Consciousness, and prove 
its faithfulness : but they are obliged to take this for granted while 
they attempt to prove it ; and, therefore, they reason in a circle. Thus, 
Kant attempted to prove the possibility of intuitions : but he was obliged 
to assume at the outset, not only their possible, but their actual truth, 
so that his proceeding was as illogical as it was preposterous. 

So when Fichte says that the Me puts forth a spontaneous effort, 
and, meeting an impediment in something external to itself, Con- 
sciousness results, he overlooks the fact that we can know nothing of 
a spontaneous effort of the Me without Consciousness, and that such 
an effort without Consciousness is a self-evident impossibility. Again, 
when he says "A is equal to A," I ask how does he know this? The 
only rational answer is, that it is self-evident, and requires no proof. 
I reply, it is self-evident that every other proposition which has the 
same amount and kind of evidence is equally certain, and equally 
unsusceptible of any proof which can add to its certainty ; and of this 
class is every proposition expressing an intuition or any present com- 
prehension. 

Similar remarks apply to Hegel's process, when he begins with pure 
nothing, and tells us that something added to nothing, makes some- 
thing, which is only a particular case of the general intuition that a 
thing is what it is. 

The doctrine of the Pyrrhonists or universal sceptics, labors under 
the same difficulty, and is liable to the same objection. Every think- 
ing being necessarily believes some proposition as certain, if it be only 
the reality of his present thought : and, therefore, the Pyrrhonist, in 
expressing himself sceptical concerning his doubts, only flies from one 
certainty to plunge into another, which is not a whit more certain 
than any other discernment. 

Note 15, Page 170. 

The law of gravitation is often expressed by saying that "matter 
attracts matter, directly as the mass, and inversely as the square of 
the distance:" but it would be much more correct to say that "pon- 
derable bodies are urged towards each other, by a force which raries 
directly as their mass, and inversely as the square of their distance," 
or. that "every tangible substance tends to move towards every other, 
with a force which varies directly as their mass, or quantity of solid 
matter, and inversely as the square of their distance." The proofs 
given of this law are quite fallacious, so far as they attempt to show 
that there is any real attraction, their authors having overlooked the 
fact that all the phenomena may result from a compulsive, instead of 
an attractive force. 

The heavenly bodies have no hold on each other ; and without this 
it is manifestly as impossible for them to attract or draic each other, 
as it is to lift a stone from the ground without having anything at- 
tached to it by which it can be lifted. Attraction without connection 
is a manifest impossibility. Another difficulty, in the way of attrae- 



Notes. 441 

tion, is, that the bodies are inanimate ; and therefore it is evidently as 
impossible for them to move either themselves or other bodies as it is 
for a rock to move itself from one mountain to another. 

Note 16, Page 200. 
The word interpretation was formerly employed in a wider sense, so 
as to include what we now term translation : but as the latter differs 
essentially from what is now generally understood by the former term, 
I have used this in its restricted signification. The old use of the 
word has evidently misled some logicians, regarding the true nature 
of interpretation. They say that the interpreter should be thoroughly 
acquainted with the language, and familiar with the subject of which 
the writing to be interpreted treats. These remarks are applicable to 
translation ; but to apply them to interpretation reminds us of the 
old advice that we should not go into the water till we have learned 
to swim : for it is only by numerous exercises of interpretation that a 
thorough acquaintance with the language can be acquired ; and we 
frequently study a work which treats of a subject regarding which we 
know little or nothing, and which we expect to learn from it. 

Note 17, Page 2-14. 

The ordinary names of the various divisions of organic nature are 
mostly Latin ; and, even when they are derived from some other 
source, they are usually given in a Latin form. Attempts have been 
made, by several naturalists, to substitute terms in their own vernacu- 
lar languages : but none of these have yet been generally adopted ; 
and it is to be hoped that they never will. For the Latin terms pos- 
sess the great advantage of being familiar to naturalists throughout 
the world, while they are free from the peculiar difficult or repulsive 
sounds that occur in others. It is evidently very desirable that scien- 
tific terms should be common to all mankind, without any change of 
spelling or pronunciation ; and, therefore, where such terms exist, they 
should be retained, till they can be superseded by better, of which there 
is no immediate prospect. 

The ordinary mode of naming genus and species is, to take the Latin 
name of some well-known genus for the generic name, and that of the 
other species, in the same language, for the specific designation. Thus, 
bos. the generic name of the ox tribe, is the Latin for the common 
ox, and bubalus for the common buffalo. The species whence the 
generic name is taken, is distinguished by some peculiar Latin epithet. 
Thus, the common ox is bos taurus, the latter word being the Latin 
for the common bull. So the cat is distinguished by adding to the 
generic term felis (which is the Latin for the common cat) the speci- 
fic term catus, a Latinized form of cat, a word which is found in sev- 
eral of the Aryan languages. The specific name for the common cat 
is, therefore, felis catvs, the lion being similarly denominated felis leo, 
the tiger, felis tigris, the puma, cougar or American lion, /efts conco- 
lor, — the panther, felis pfirdus, and so forth. So the dog is termed 
cards familiaris, canis being the Latin for clog: canis lupus is the wolf, 
and canis vufpes, the fox. 

If the- species or genus has no Latin name, naturalists adopt the 
native name, or one which indicates a striking peculiarity of the di- 
vision, or the name of its discoverer, or of some of his friends or favor- 

T2 



442 Notes. 

ites. Thus, bos arnee is the specific name of the arnee, or Indian buf- 
falo — bos grunniens, that of the yak, or grunting ox of Central Asia — 
and bos coffer, the South African buffalo. So the gigantic genus of 
conifer recently discovered in California, is termed by some Washing- 
tonia, and by others Wellingtonia, while a species of pine lately discov- 
ered in the same country, is termed pinus Jeffreyi, from Jeffrey, its 
discoverer. 

It is to be regretted that, in naming newly discovered groups, the 
principle has not been universally followed of adopting a name which 
indicates the most remarkable peculiarity of the division, since other 
methods furnish no direct information regarding its nature. 

Note 18, Page 252. 

The categories of Aristotle consisted of a few heads, such as time, 
place, quality, &c, to one or other of which it was supposed every ques- 
tion might easily be referred ; and they were apparently designed to 
assist in finding and keeping in view the point at issue in an investiga- 
tion. But all such attempts are futile. For either the heads will be 
so general as to be good for nothing, or the enumeration will run into 
a mass of details too burdensome for the memory, and possibly inac- 
curate or incomplete after all. 

A careful consideration of the subject will always show the nature 
of the question much better than any categories : for many questions 
are of a complex nature, and the inquiry branches into several heads, 
so that the categories would mislead, rather than guide. 

Note 19, Page 334. 
I use the singular, instead of the plural, form of the names of sev- 
eral sciences, not merely because all nations except those who speak 
English, do so, but because the sciences are one, and, therefore, the 
singular is the proper form. It is, in reality, as absurd to talk of Me- 
chanics, Optics and Ethics, as to speak of Logics, Rhetorics and As- 
tronomies, although our ears are more familiar with the former than 
with the latter terms. 

Note 20, Page 340. 
Ethnography differs so widely in its nature and subjects from what 
is properly termed Geography that they ought to be distinguished by 
different names. The latter is purely scientific, while the former is 
only partially so. Yet its truths possess so much generality that they 
cannot properly be classed with History or Biography, which discusses 
only particular facts and occurrences. 

Note 21, Page 347. 
As the general uses of knowledge have been discussed in the Intro- 
duction, those pointed out in Part IV. are only the special uses of the 
various branches. 

Note 22, Page 347. 
Various methods have been employed in establishing the funda- 
mental principles of the Higher Analysis, or, as it is often termed, the 
Infinitesimal Calculus. But the method of limits, or of prime and ul- 



Notes. 443 

timate ratios, which was first employed by Newton, is that which is 
now generally adopted ; and it appears to be the best, as it leads to 
the required principles by the clearest and easiest steps. The princi- 
pal difficulty attending it is, that we cannot comprehend the infinity 
of changes or variations which it assumes ; and hence we are apt to 
conclude that they cannot be. But the following simple theorem en- 
ables us to surmount the difficulty. 

A quantity ivhich gradually diminishes, so that it becomes less than any 
assignable quantity, vanishes, or becomes nothing. 

If the quantity does not become absolutely nothing, let its least value 
be x : then, since it becomes less than any assignable quantity, it be- 
comes less than-^j: that is, a quantity becomes less than the thou- 
sandth part of itself, which is absurd. Therefore the diminishing 
quantity becomes nothing. 

It follows, as a corollary, from this theorem, that when a quantity 
approaches indefinitely near another, it ultimately coincides with it, 
or, as it is otherwise expressed, it becomes equal to it at the limit. 

Another, and more general, corollary is, that a quantity which be- 
comes less than any assignable quantity, may be rejected in a final 
expression, without changing the value of the expression. The former 
corollary is only a particular case of this one. For, let C be a con- 
stant quantity, x a variable which approaches indefinitely near it, and 
d x the quantity by which x differs from C: then 

x+d x— C ; 
and, therefore, by the second corollary, when d x becomes indefinitely 
small, or less than any assignable quantity, 

x=C, 
which is the first corollary, analytically expressed. 

These theorem and corollaries also furnish the best foundation for 
the doctrines of proportion, as they enable us to treat incommensura- 
bles like commensurables. 

Note 23, Page 352. 

To the inductive laws of motion usually given by writers on Mechan- 
ic, should be added the following : 

The momentum of a body is proportional to its 7tiass multiplied by its 
velocity. This law is sometimes introduced as a definition : but it is 
evidently a theorem ; and it is established like other inductive laws 
of motion. 

The momentum of a body means its moving force, or its power to 
move, penetrate, break, tear, or crush, another body with which it 
comes in contact, or which it otherwise affects. The mass of a body 
means its quantity of solid matter, which is generally measured by its 
weight. The velocity of a body is either actual or virtual. The for- 
mer is that with which it actually moves : the latter is that with which 
it would move, if some counteracting force were withdrawn, and is 
that meant in the proposition. 

Note 24, Page 358. 
Attention has now been so extensively directed to every branch of 
Astronomy that there is little probability of any entirely new field be- 
ing discovered ; yet the immense subject of the fixed stars still offers 



444 Notes. 

many problems for future observations, which it will require many 
generations to solve ; and even the field of the solar system is by no 
means exhausted. 

Note 25, Page 362. 

The identity of the law of intensity of light, heat and electricity with 
that of the force of gravitation, is an indication that the phenomena 
of gravitation result from undulations of ether, passing incessantly, at 
very short intervals, through every point, in all directions. The fact 
that we can clearly see any one point in a room from any other, 
proves that this is the case with the waves of light ; and it may, there- 
fore, hold true of those of gravitation. 

If we suppose these undulations so small that they penetrate through 
all ponderable bodies, and impinge against the atoms which compose 
them, those phenomena will be a necessary consequence. A single 
atom would be apparently unaffected, since the forces acting on it in 
all directions would be equal: but when there were two atoms, the 
waves on the outer sides would force them together, because those 
flowing in the opposite direction -were stopped by the inteiwening body. 
The nearer the atoms, the more interfering waves would be stopped ; 
and the force would follow the law of the inverse square, for the same 
reason that a person at two yards from a fire receives only one fourth 
as much heat as when he is one yard distant. As every atom would 
be similarly affected, gravity would vary directly as the mass, or num- 
ber of atoms. 

According to this view, gravitation is a compulsive, and not an at- 
tractive force, as it is constantly termed ; or, in other words, it is a 
pushing, and not a pulling force. It would also follow that gravita- 
ting bodies do not in any way affect each other, except where they are 
in contact. But these results can form no real objection to the doc- 
trine : for the demonstrations given of the law of gravitation wholly 
fail to prove that there is any real attraction, or that the bodies really 
affect each other. All they prove is, that the bodies move towards 
each other ; and this is explained by the one theory quite as well as 
by the other. 

We may suppose that the waves of light, heat and electricity origin- 
ate in the gravitation waves being disturbed, and thus generating them, 
owing to the peculiar form, position or motion of the atoms of ponder- 
able bodies, although these positions and motions might have been 
produced, in the first instance, by the gravitation waves themselves. 

If we farther suppose that the gravitation waves sometimes impinge 
against substances which they cannot permeate without causing their 
parts to adhere closely to each other, either directly or by means of 
new waves, we should have an explanation of cohesion and chemical 
affinity. 

The elasticity of bodies might be explained by supposing that wher- 
ever some of the atoms were pulled a little apart while others were 
forced nearer than usual, new waves were generated which exerted a 
repellent action on the latter, and a compulsive force on the former. 

The peculiar phenomena of heat and electricity are easily explain- 
ed on this hypothesis. Thus, the melting and expanding power of 
heat, and its influence on chemical action, would result from its strong 
waves simply counteracting the cohesive force of those of gravitation, 
as in fluids ; or they might even produce a repulsive contrary force, 



Notes. 44-5 

as in gases. In both cases we might expect the distance of the atoms 
from each other to be increased, which would account for the expan- 
sion that usually takes place, although the form of these atoms might 
be such that they would become more compactly arranged, and con- 
sequently occupy less space, on being heated, as in the case of melted 
iron, and water near the freezing point. 

The effects of heat and electricity on chemical action would result 
from their loosening the particles, and thus favoring a combination 
of the elements, in some cases, while the increased expansibility of a 
gas would'cause it to fly off, in other cases, as in the common process 
of burning limestone, or what is technically termed roasting metallic 
ores. 

The attractive and repulsive phenomena of electricity would be 
produced by its waves interfering with each other, according to the 
various directions in which they flowed. So, latent heat would result 
from the waves being destroyed by resistance in one case, like those 
of light falling on a black body, and being again re-generated from 
the rapid motion of the particles, in assuming their former state. 

Thus the gravitation waves, and the peculiar forms of the various 
ponderable substances, may account for a great portion of the phe- 
nomena of the physical creation, as their immediate causes. But we 
must look to a presiding Intelligence, not only to form and arrange 
those substances originally, but also to sustain the motions of the 
ethereal particles, by continued and most powerful acts. This is pos- 
sibly effected by undulations propagated from a center, as light pro- 
ceeds from the Sun, and reflected from the various points of a solid 
sphere, surrounding the visible creation. 

If it be objected that this arrangement would render gravitation of 
unequal force, I answer that we have no proof it is not so ; we do not 
know, for instance, that the force of gravitation is the same at the 
nearest, and much less at the remotest, fixed star, as it is at the Sun ; 
and the space occupied by the solar system is only a very small part 
of the universe. It may be further answered that the particles of 
ether may be so arranged as to compensate for the unequal action of 
the central force, in different parts of space. 

Note 26, Page 364. 
Organic specimens have generally been preserved by drying them, 
or putting them in alcohol ; but they could be preserved in a vacuum 
better, probably, than by any other means, although this method has 
been little used, if at all. 

Note 27, Page 373. 
The grand outlines of Geology have already been clearly traced : 
but the science is very extensive, and much remains to be done, in 
filling up details, modifying propositions which may have been too 
loosely or generally expressed, and settling doubtful or disputed points. 
Several of the terms, also, should be superseded by others, of a more 
general and scientific character. 

Note 28, Page 376. 
Logic properly embraces the few truths relating to the general prop- 
erties of beings, which have been attempted to be formed into a sep- 



446 Notes. 

arate science, under the name of Ontology. This is variously defined 
as the science of "being in general," and "that which investigates the 
nature and properties of being or reality, as distinguished from phe- 
nomena or appearances." Our knowledge of such properties is whol- 
ly intuitive, and far too scanty to form a science. 

What some term the science of JEsthetics is only a part of that di- 
vision of Psychology which treats of the emotions. Discussions re- 
garding the modes of producing ajsthetical emotions belong to art, 
and not to science. 

To Logic and Psychology belong most of the subjects discussed un- 
der the vague names of Pneumatology and Metaphysics, and all the rest 
properly belong to other branches of knowledge, so that those divisions 
should be discarded. 

Note 29, Page 385. 
The subjects discussed under the name of Political Economy belong 
partly to Morality, partly to Jurisprudence, and partly to Technology. 
The combination forms a compound of incongruous elements which 
were much better discussed under the heads to which they respective- 
ly belong. What relates to laws, is best discussed in Jurisprudence ; 
the duties of an individual, in regard to his vocation, belong to Mo- 
rality ; and the mode in which an art or profession should be earned 
on or exercised, in order to make it most useful or profitable, rightly 
belongs to Technology, and has nothing to do with political science. 

Note 30, Page 390. 

From misunderstanding some passages in the eleventh chapter of 
Genesis, many have supposed that the original language of mankind 
was miraculously formed into several at Babel. But there is no real 
foundation in Scripture for any such opinion. The literal rendering 
of the first verse of the chapter referred to, is — "And the whole Earth 
was of one lip and of one words." The last term certainly means 
language, as it does not admit of any other interpretation in this 
place: and, consequently "lip" must mean something else; otherwise 
the expression would be absurdly tautologous : and it is observable that 
the expression "words" is not repeated, in any part of the narrative. 

The literal rendering of the last clause of the seventh verse is — 
"that a man will not hear the lip of his neighbour," which is well 
rendered in the old Greek and Latin versions — "that one will not 
hear the voice of his neighbour." The word rendered " hear" (which 
is of very frequent occurrence in the Old Testament), properly signi- 
fies hear in Hebrew as much as this does in English. It is sometimes 
employed figuratively to denote understand : but this is unusual. Here 
it evidently means listen to or regard; and the confusion spoken of 
was simply dissension, arising from differences of opinion, the instru- 
ment, by a common figure of speech, being put for that which is ex- 
pressed. 

The more closely and extensively languages are examined, the more 
irresistible appears the evidence of their common origin. The old 
philologists were often mistaken in their views regarding the deriva- 
tion of languages : for when they found several that closely resembled 
each other, they inferred that all the rest must have sprung from the 
one which they thought the oldest, a process like inferring that the 



Notes. 447 

oldest-looking of several sisters must be the mother of all the rest. 
Yet the affinities on which they argued were mostly real. 

The theory which attributes the affinities of language to the simi- 
larity of the organs of speech, in the various races of men, is refuted 
by several well-known facts. Thus, the Turks resemble the Germans 
in physical structure, much more than do the Hindoos ; and yet the 
languages of the latter resemble the German.much more closely than 
the Turkish does. Again, words which appear to be derived from 
imitating natural sounds, widely differ, in various languages, while 
words which have no such origin, are alike. Thus, the words for 
weep are entirely different, even in several of the kindred Aryan lan- 
guages, while the word sack is found, with the same signification, in 
several distinct classes of languages, along the whole length of the 
old world. 

If we request several unconnected persons to imitate some natural 
sound, such as the note of a bird, they will generally pronounce it very 
differently, while the similarities of language are apparent in words 
whose particular form must have been casual, and also in the struc- 
ture of language, as well as in the vocabularies. 

To compare human speech, with its myriads of words and its com- 
plexity of structure, to the few instinctive and inarticulate cries of the 
lower animals, could proceed only from persons who never properly 
examined the subject. To those who have, the comparison will ap- 
pear absurd, as it really is. 

It is observable, however, that the facts just mentioned do not war- 
rant Miiller's theory, that language has sprung from "phonetic types, 
produced by a power inherent in human nature." For words have 
been so much changed that the onomatopoetic origin of many will 
have disappeared in that way, while, in other cases, it will have van- 
ished by mere epithets or learned terms having usurped the original 
words. Of this, the whip-poor-will furnishes a recent instance. Al- 
though the bird is generally known by no other name throughout the 
United States, yet its scientific name is totally different, being capri- 
mulgus vocifei'us. 

That language originated partly in onomatopoeia and ejaculation, 
admits of no doubt ; and when we consider the power of man to form 
compounds, and the natural tendency to contraction and alteration, 
during successive ages, Ave shall see that those two sources, taken in 
connection with man's ordinary intellect, are amply sufficient to ac- 
count for all the phenomena of speech. The supposed "inherent 
power" is, therefore, destitute of a tittle of evidence that it ever ex- 
isted : that it does not exist now, is admitted. The slightest appli- 
cation of the doctrine of permutations and combinations, will show 
that onomatopoetic and instinctive ejaculations would readily produce 
many more words than the totai number of primitives found in any 
language. 

The more complex structure of Sanscrit and Greek, compared with 
English or French, has been applied as an argument in support of the 
original superiority and divine origin of language. But, besides the 
facts already stated, there are several others, which show the worth- 
lessness of this argument. Many of the aboriginal languages of Af- 
rica and America are much more complex than either Sanscrit or 
Greek ; and yet they are found ill adapted for conveying thought on 
abstract subjects, with either force or precision. 



448 Notes. 

The copiousness of inflection, which has been frequently adduced as 
a striking proof of the superiority of the ancient classic languages, 
originated chiefly in colloquial blunders, or in confounding distinc- 
tions which ought to have been preserved. The personal inflections 
of verbs, for instance, arose from confounding the personal pronouns 
with the verbs of which they were nominatives. 

As a simple machine, which performs well all the requisite func- 
tions, is superior to one which contains many useless parts ; so a lan- 
guage which contains no useless inflections, is, so far, superior to one 
which exhibits many such cumbrous appendages. Thus, in the in- 
stance just mentioned, it is better to indicate the person by a separate 
word, as in English, than to blend nominative and verb, as is done in 
Latin and Greek. The natural consequence of the latter practice has 
been, that the meaning of the affix was lost ; and hence the pronoun 
came to be repeated, or used superfluously. Ego am-o is — I love-I ; 
illi am-ant is — they love-they; and homines dic-unt is — men say-they. 

The wide room for variety in the collocation of words, allowed by 
the classic languages, tended to produce confusion in the speaker or 
writer, and impeded a right understanding of his expressions, on the 
part of his hearers or readers. 

As every ancient language must have undergone numerous altera- 
tions from time to time, long prior to the invention of' writing, it fol- 
lows that the original language of mankind can nowhere be found. 
Nor can we say, with any degree of certainty, what language most re- 
sembles it. But as it must have been a very rude and scanty speech, 
the question is one of little interest, and of no practical importance. 

Note 81, Page 394. 
Although much has been already accomplished, yet the application 
of scientific principles to the improvement of the arts still presents a 
wide field for invention. For many of those who attended to this 
subject either failed to see the most pressing wants of art, or mistook 
the best modes of supplying them. Hence their inventions were either 
unimportant or inefficient. 

Note 32, Page 403. 

Besides the Christian, the following are the principal epochs used 
in History : 

1. The Creation of Man, 3760 years before Christ, according to the 
Hebrew reckoning, or 5509 according to the Septuagint. This epoch 
is used by the Jews, and often by Christians, in treating of events 
prior to the Christian era. 

2. The Olympic epoch of the Greeks, 776 years B.C., from which 
they reckoned by olympiads, or periods of four years. 

3. The Building of Rome, 752 years B.C. This epoch was long 
used by the Romans. 

4. The epoch of Budda, 544 B.C., used by the Buddists through- 
out Southern and Eastern Asia. 

5. The Samvat, or era of Vicramaditya, beginning 56 years B.C., 
used by the Northern Hindoos. 

6. The Saca, or era of Sulwanah, commencing A.D. 78, used in 
Southern and Western India. 

7. The Hejira, or flight of Mohammed from Mecca. 16th July, 
A.D. 622. generallv used bv Mohammedans. 



INDEX. 



A. 

Aberrancies, definition of, 250. 
" illustration of, 251. 

" ofconfusion, 306-3 16. 

" of appeals to authori- 

ty, 316-320. 

Aberrancies, of appeals to desires, 
320-324. 

Aberrancies, table of, 327. 

Abridgements, how distinguished, 
233. 

Absolute proposition, definition of, 
39. 

Abstract quantity, principles re- 
garding, 5-1-58. 

Abstraction, definition of, 35. 
" two kinds of, 35. 

Abstracts, uses of, 138, 417. 
• Accumulating probabilities, soph- 
ism of, 299. 

Acoustic, definition of, 335. 

" foundations and uses of, 
354. 

Adopting a mean, paralogism of, 
280, 281. 

^Esthetics, its nature, Note 28, 446. 

^Etiology, definition of, 336. 

Affirmative proposition, definition 
of, 39. 

Agencies (see Causes and Determ 
ining Conditions). 

Algebra, definition and divisions 
of, 333. 

Algebra, uses of, 346, 347. 

Alphabets, origin of, Note 12, 438, 
439. 

Altering propositions, sophism of, 
288,289. 

Alternative proposition, definition 
of, 39. 

Ambiguity, latent, 207. 

Ambiguous expression, paralogism 
of, 276. 



Ambiguous expression, modifica- 
tions of, 276, 277. 

Analogy, definition of, 158. 
" uses of, 158, 159, 178. 
" abuse of, 159. 

Analysis, Mathematical, definition 
of, 333. 

Analysis, Mathematical, charac- 
teristics of, 345. 

Analysis, Mathematical, uses of, 
346, 347. 

Analysis, mental, remarks' on, 160. 

Analytical Geometry, definition 
and divisions of, 333, 334. 

Analytical Geometry, its relation 
to Analysis, 345, 346. 

Analytical Geometry, uses of, 350. 

Anatomy, definition and divisions 
of, 336. 

Anatomv, foundations and uses of, 
365. 

Angles, principles regarding, 55. 

Animate substances, definition of, 
5S. 

Animate substances, principles re- 
garding, 58-60. 

Antecedent, how distinguished 
from cause, 61. 

Antecedent and consequent, mne- 
monic law of, 420. 

Antiquated significations, when to 
be adopted, 202, 203. 

Antiquities, definition of, 310. 

Appeals to authority, aberrancies 
of, 316-320. 

Appeals to desires, aberrancies of, 
320-324. 

Apprehensions, nature of, 32. 

" inferences from, 33, 

74-85. 

Apprehensions, reality of, 45, 46, 
73. 

Apprehensions, requisite to, 46. 



450 



Index. 



Apprehensions, how distinguished 

from ideas, 46, 47, 72, 73. 
Apprehensions, distinct from their 

causes, 73, 74. 
Apprehensions, subsidiaries of, 

86-91. 
Apprehensions, admit of no proof, 

128. 
Apprehensions, safe assumptions 

regarding, 130. 
Apprehensions, errors regarding, 

131, 132. 
Approximation, method of, 88. 
Archeology, definition of, 340. 
Arguments, nature of, 68, 69. 

" modes of testing, 68- 

70, 137-139, 146, 147, 264, 265. 
Arguments, illustration of, 69. 

" by what invalidated, 

251. 
Aristotelians, their division of a 

proposition, Note 2, 435. 
Aristotelians, their doctrine of rea- 
soning and the syllogism, Note 

5, 436, 437. 
Aristotle's Categories, Note 18, 

442. 
Arithmetic, definition of, 333. 

" its uses, 346. 
Art, definition of, 339. 

" various kinds of, 340. 

" characteristics and founda- 
tions of, 392, 393. 
Art, requisites to proficiency in, 

393. 
Art, how related to Theorv, 393, 

894. 
Art, field for improvements in, 

Note 31, 448. 
Association of Thoughts (see 

Thoughts). 
Assuming conditions, paralogism 

of, 277. 
Assuming the question, paralogism 

of, 267, 268. 
Astronomy, definition and divis- 
ions of, 335. 
Astronomy, character and uses of, 

354. 
Astronomy, modes of establishing 

its truths, 354-358. 
Astronomy, future discoveries in 

Note 24, 443, 444. 
Attention, nature of, 34. 



Attention, its importance, 46-48, 

121, 122, 214. 
Attention, how secured, 253, 254, 

414. 
Attention, mnemonic law and rules 

of, 413-415. 
Attraction of gravitation, remarks 

on, Notes 8 and 15, 437, 440. 
Attributes, extrinsic, 79. 

" intrinsic, 79-85. 
Authority, fallacies of appeals to, 

316-320. 
Authorship, how ascertained, 229- 

232. 
Axioms, mathematical, what they 

are, 345. 

B. 

Begging the question, paralogism 
of, 266-267. 

Beings, definition of, 58. 
" various kinds of, 58. 
" principles regarding, 58- 
60. 

Beings, how existence and prop- 
erties of some known, 75-85. 

Belief, definition of, 49. 

" how distinguished from 
knowledge, 30, 49. 

Belief, common error, 315. 

Bias, its sources, and influence on 
testimony, 214, 215, 217. 

Bias, how its presence may be as- 
certained, 215, 216. 

Biblical Theology, definition of, 
338. 

Biblical Theology, foundations and 
uses of, 379. 

Biblical Theology, study of, 379- 
381. 

Biographv, definition and divis- 
ions of," 341, 343. 

Biographv, how related to Historv, 
403. 

Biography, its uses, 403, 404. 

" common defectsin,404. 

Body, definition of, 62. 

" natural tendency of, 170, 
179. 

Books, uses of, 141, 142, 148. 
" selection of, 149, 150. 
" study of, 150, 151. 
" means of ascertaining their 
origin, 233. 



Index. 



451 



Botany, definition and divisions of, 

336. 
Botany, sources and uses of, 364. 

C. 

Calculus, Infinitesimal, remarks 

on, 347. Note 22, 442, 443. 
Categories of Aristotle, Note 18, 

442. 
Causation, principles of, Gl-63, 

175-177, 180. 
Causation, sophisms of, 292-298. 
Cause and effect, mnemonic law 

of, 420. 
Causes, definition of, 61. 

" how their nature known, 

Note 7, 437. 
Causes, principles regarding, 61- 

63, 175-177, 180. 
Causes, necessary and contingent 

165. 
Causes, inadequate, 166. 

" uses of a knowledge of, 

166-169. 
Causes, important distinction, 169. 
" efficient and conditional, 

169, 170. 
Causes, immediate, mediate, and 

ultimate, 170. 
Causes, only ultimate causes, 170, 

180. 
Causes, frequent error, 170. 

" modes of determining, 171 

-175. 
Causes, criterions where these fail, 

175-177. 
Causes, sole and joint causes, 177, 

178. 
Causes, uses of analogy, 178. 
" " of experiments, 178, 

179. 
Causes, new agencies, 1 79. 

" chain of causes, 179, 180. 
" reactive agencies, 181. 
" cautions, 181, 297. 
" fallacies regarding causes, 

292-298. 
Causes, distinct from laws, 295. 
Certainty, foundations of, 45-48. 
" how distinguished from 

probability, 66,301. 
Chain of reasoning, definition of, 65. 
Chain of reasoning, illustration of, 

66. 



Chain of reasoning, requisites to 
validity of, 66. 

Chain of reasoning, how related to 
arguments, 68, 69. 

Change, nature of, 69. 
" conditions of, 60. 
" principles regarding, 60- 
63, 437. 

Characteristic marks, definition of, 
64. 

Chemistry, definition and divis- 
ions of, 337. 

Chemistry, foundations and uses 
of, 371, 372. 

Chemistry, important distinction, 
371. 

Children's testimony, remarks on, 
217, 218. 

Chronology, definition of, 341 . 

" uses and foundations 

of, 402, 403. 

Circumstantial evidence, 211, 212. 

Classes, organic, formation and 
naming of, 241-243, 441, 442. 

Classification, definition of, 238. 

" mental and physic- 

al, 238, 239. 

Classification, how distinguished 
from generalization, 238. 

Classification, main objects of men- 
tal, 239, 240, 417. 

Classification, principles of, 240. 
" chief rules of, 240, 

241. 

Classification, of organisms, 241- 
244. 

Classification, application of prin- 
ciples, 244, 245. 

Classification, influence of preju- 
dices, 245. 

Cognitions, definition of, 30. 

" test of, 48, 244-246. 

Combination, definition and use 
of, 69. 

Commemorations, mnemonic ef- 
fects of, 425, 426. 

Common-place books, use of, 428. 

Comparison, definition and nature 
of, 101. 

Complex proposition, definition of, 
39. 

Compositions, modes of ascertain- 
ing their origin and character, 
229-237. 



452 



Index. 



Compound proposition, definition 

of, 39. 
Comprehension of terms, definition 

of, 191. 
Comprehension, mnemonic law of, 

415. 
Comprehensions, definition of, 29. 
" what learned bv, 

29, 33, 34. 
Comprehensions, require no proof, 

128. 
Comprehensions, paralogisms of, 

269-271. 
Conceptions, definition and nature 

of, 35, 3G. 
Conceptions, always particular, 98, 

99. 
Conceptions, their reality, how 

known, 128. 
Conclusions, definition of, 65. 

" requisites to validity 

of, 66, 67. 
Conclusions, modes of testing, 67, 

68, 136-139, 264, 265. 
Conditional causes, definition of, 

169, 170. 
Conditional proposition, definition 

of, 39. 
Conflicting opinions, aberrancy of, 

317. 
Confounding cause and effect, 

sophism of, 293, 294. 
Confounding different senses, para- 
logism of, 283. 
Confounding means and end, aber- 
rancy of, 316. 
Confusion, aberrancies of, 307-3 1 6. 

" sophisms of, 287-289. 
Connective, definition of, 51. 

" various forms of, 68. 

" necessary character 

of, Note 5, 436. 
Consciousness, definition of, 30. 

" futile attempts re- 

garding, Note 14, 440. 
Contiguitv, mnemonic law of, 419, 

420. 
Contingent connective, sophism of, 

300. 
Contingent knowledge, nature of, 

of, 31. 
Contingent knowledge, primary 

modes of acquiring, 71-93, 96, 

97. 



Contingent knowledge, primary 

I modes of retaining, 93-98. 

Contradictory propositions, defini- 
tion of, 38. 

Contraries, mnemonic law of, 422, 

' 423. 

Contrarv proposition, definition of, 
,38. 

Controverted subjects, remarks on, 
142, 143. 

'Conversation, its logical charac- 
ter, 142. 

Converse of a proposition, defini- 
tion of, 3S. 

Converse of a proposition, when 
true, 288. 

Copying, why of little mnemonic 

j value, 428. 

[Corruptions of written testimonv, 

[ 232, 233. 

Counting witnesses, paralogism of, 

j 281. 

Cramming, evils of, 145, 414, 415, 

J 431, 432. 

Credulity, paralogism of, 2S1, 282. 

Criterion of intuitions, 267. 
" of reasoning, 65-71. 
" of truth, 48. 

Criterions of testimony, 213-219. 

Crystalography, definition of, 33S. 

Curves, particular use of, 91, 92. 

D. 

Dates, how ascertained, 402, 403. 

Dead languages, how learned, 
385-389. 

Deciding bv appearances, aberran- 
cy of, 311, 312. 

Deciding bv character, aberrancv 
of, 309. 

Deciding bv consequences, aber- 
rancy of, 309, 310. 

Deciding bv motives, aberrancy of, 
310, 311. 

Deduction, definition of, 130. 

" error regarding, Note 

13, 439, 440. 

Deduction, tests of, 136, 137. 

Definitions, verbal and real, 192. 
" rules of verbal, 192,193. 
" characteristics of good, 

193. 

Definitions, when required and 
when not, 429. 



Index. 



453 



Desires, principles regarding, 62, 

63. 
Desires, aberrancies of appeals to, 

320-324. 
Desultory habits, evils of, 122, 123. 
Determining conditions, definition 

of, 60. 
Determining conditions, principles 

regarding, 60-63. 
Deviations, evils of, 145. 
Dictionaries, sources and uses of, 

385-389. 
Difficulties, art of surmounting, 

144-146. 
Diminishing improbability, soph- 
ism of, 305. 
Diminishing probability, sophism 

of, 305. 
Direct discovery, nature of, 154. 

" " observations on, 

155, 156. 
Direct proof, definition of, 134, 

135. 
Discernments, definition of, 30. 

" require no proof, 

128. 
Discordant opinion, sophism of, 

301, 302. 
Discovery, direct, 154-156. 

" indirect, 154, 156-162. 

" " usual course 

of, 159. 
Discovery, indirect, chief difficulty, 

160. 
Discrepancies in testimony, 220- 

232. 
Disjunctive proposition, definition 

of, 39. 
Disposition proper for investiga- 
tion, 119-121. 
Division, nature of, 239, 240. 
Dogmatism, character and origin 

of, 119, 120. 
Duration, principles regarding, 53, 

54. 
Duration, errors regarding, Note 

6, 437. 
Dynamic, definition of, 334. 

E. 

Education, definition of, 340. 

" its importance, 395, 

396. 
Effects, definition of, 61. 



Effects, how distinguished from 

consequents, 61. 
Effects, principles regarding, 61-63. 
" importance of knowing, 

166-169. 
Effects, how sometimes discovered, 

167, 168. 
Effects, peculiar use of, 169. 

" modes of tracing, 171-181. 
" important principle, 180. 
" reactive effects. 181. 
" cautions, 181, 297. 
Efficient causes, definition of, 169, 

170. 
Electric, definition and divisions 

of, 335, 336. 
Electric, foundations and uses of, 

361. 
Electricity, probable nature of, 362. 
Electrodynamic, definition of, 335, 

336. 
Electrodynamic, importance of, 

361. 
Electromechanism, definition of, 

336. 
Electromechanism, us.es of, 361. 
Electrostatic, definition of, 335. 

" importance of, 361. 

Emotional sirts, nature of, 340. 
Emotions, definition of, 34. 
" what known by, 34. 
" mnemonic law of, 421, 

422. 
Emotions, important distinction, 

422, 432. 
Empiricisms, definition of, 101. 

" how formed, 100, 

101,312. 
Empiricisms, uses of, 108. 

" not laws of nature, 

109. 
Enemies' opinions, sophism of, 303. 
Epochs, principal used, Note 32, 

448. 
Equanimity, advantages of, 119, 

122, 430. 
Equanimity, its influence on re- 
membrance, 430. 
Equanimity, how to be secured, 

432. 
Equivocation, paralogism of, 276. 
Eras (see Epochs). 
Errors, sources of, 45-48, 131, 

132. 



454 



Index. 



Errors, means of avoiding, 46-49, 
71-75, 261-265. 

Errors, why powerful, 260. 

Essential properties, definition of, 
64, 242. 

Ether, nature and probable effects 
of, 335. 

Ethereal sciences, definition and 
divisions of, 335, 336, 342. 

Ethereal sciences, nature and uses 
of, 358. 

Ethereal sciences, probable origin 
of their phenomena, 362 ; Note 
25, 444, 445. 

Ethic, definition of, 338. 

" foundations and uses of, 
381, 382. 

Ethic, study of, 382, 383. 

Ethnology, definition of, 336-366. 

Ethnography, definition and divis- 
ions of, 339, 340, 343. 

Ethnography, foundations and uses 
of, 391, 392. 

Ethnography, why distinguished 
from Geography, Note 20, 442. 

Etymologies, paralogism of follow- 
ing, 284. 

Evidence, definition of, 129. 

" general principles of, 
209-212. 

Evidence, signs, 129, 209, 210. 
" testimony, 129, 210. 
" concurring, 210, 211. 
" circumstantial, 211,212. 
" criterions of testimony, 
212-219. 

Evidence, concurring testimonies, 
219. 

Evidence, discrepancies, 220-222. 
" probable testimony, 222- 
224. 

Evidence, influence of prejudices, 
223, 224. 

Evidence, futile distinctions, 225, 
226. 

Evidence, various kinds of testi- 
mony, 226-228. 

Evidence, written testimony, 227- 
237. 
(See Signs, and Testimony.) 

Exaggerating improbability, soph- 
ism of, 305. 

Exaggerating probability, sophism 
of, 304, 305. 



Excluding causes, sophism of, 296. 
" effects, sophism of, 297. 

Exclusion, principles of, 63-65. 

Existence of self, how known, 75. 

Experiments, definition of, 90. 

" uses and objects of, 

90, 91. 

Experiments, two kinds of, 90. 

' ' rules regarding, 161. 

Explicit testimony, 226. 

Expressions, importance of attend- 
ing to, 143, 144. 

Expressions, rules of proper, 190, 
191. 

Expressions, five classes of, 200, 
201. 

Extension, method of, S8, 89. 

" or Space, principles re- 

lating to, 53, 54. 

Extension or Space, errors regard- 
ing, Note 6, 437. 

Extension of terms, definition of, 
191. 

External signs, 97, 98. 

Extracts, uses of, 428, 429. 

" how used in remem- 
brance, 425-427. 

Extrinsic probability, remarks on, 
224. 

Extrinsic properties, 79. 



Faculty, definition of, 32. 
Fallacies, definition of, 249. 
" operation of, 249. 
" evils of, 249, 250. 
" three classes of, 250. 
" universal defect in, 250. 
' ' independent of each oth- 
er, 251. 
Fallacies, illustration of, 251. 
" sources of, 252-254. 
" effects of prejudices on, 
254-260. 
Fallacies, means of guarding 

against, 261-265, 324. 
Fallacies, common error, 266. 
" table of, 325-327. 
(See Paralogisms, Sophisms, 
and Aberrancies.) 
Fallacious implication, paralogism 

of, 286. 
Fallacious propriety, paralogism 
of, 286. 



Index. 



455 



False association, paralogism of, 

274. 
False cause, sophism of, 292, 293. 

" effect, sophism of, 293 
Falsehood, paralogism of, 278. 
Families, organic, formation and 

naming of, 243, 441, 442. 
Fiction, how to be detected, 237, 

402. 
Figurative expressions, abuse of, 

196. 
Figurative interpretation, when 

proper, 201, 202. 
Figures, Aristotelian, remarks on, 

Note 5, 437. 
Flattery, why powerful, 259, 260. 
Following etymologies, paralogism 

of, 284. 
Force, definition of, 59. 

" principles regarding, 59, 

61-63. 
Forgetfulness, paralogism of, 275. 
Forgetting, nature of, 97. 
Fraud, chief source and support 

of, 21, 22. 
Friends' opinions, sophism of, 299. 
Futurity, why often undervalued, 

257, 321. 
Futurity, extent and importance 

of our knowledge of, 405, 406. 
Futurity, sources of such knowl- 
edge, 34, 406-410. 

G. 

Galvanism, definition of, 336. 

" importance of, 361. 
Gases, characteristic of, 335-354. 
Genera, formation and naming of 

organic, 241-243, 441, 442. 
General belief, aberrancy of, 317. 
" Geography, definition of, 

337. 
General Geography, sources and 

uses of, 368-370. 
General Grammar, definition of, 

339. 
General Grammar, uses of, 391. 
" proposition, definition of, 

39. 
General terms, uses of, 36, 190 
" " what they denote, 

99. 
Generalization, definition and 

kinds of, 36, 98. 



Generalization, uses of, 99. 

" various processes 

of, 99-107. 

Generalization, superior and sub- 
ordinate laws of, 107. 

Generalization, uses of empirical, 
108. 

Generalization, advantages of ex- 
tending, 108, 109. 

Generalization, how distinguished 
from classification, 238. 

Generalization, sophisms of, 289- 
292. 

Generalization, its influence on re- 
membrance, 415, 416. 

Geognosy, definition of, 337. 

" sources and uses of, 

370. 

Geographical sciences, definition 
of, 334. 

Geographical sciences, divisions of, 
337, 338, 342. 

Geographical sciences, character 
and study of, 367, 368. 

Geography, definition and divis- 
ions of, 337. 

Geography, sources and uses of, 
368-371. 

Geology, definition and divisions 
of, 337. 

Geology, foundations and uses of, 
372, 373. 

Geology, defects of, Note 27, 445. 

Geometry, definition and divisions 
of, 333, 334. 

Geometry, how connected with 
Analysis, 345, 346. 

Geometry, uses of, 346, 347. 

God (see Theology). 

Grammar, sources and uses of, 
385-388. 

Gravitation, law of, 170. 

' ' objectionable views of, 

Notes 8 and 15, 437, 440. 

Gravitation, how established, 356. 
" inferences from, 356- 

358. 

Gravitation, probable origin of its 
phenomena, Note 25, 444, 445. 

H. 

Habits, influence of, 121, 418. 
" various kinds of, 121-126. 
" two important laws of, 125. 



456 



Ixdex. 



Habits, how good to be formed, 

127, 431. 
Harmonizing conclusions, sophism 

of, 300. 
Health, its importance, 148. 153, 

418, 430. 
Health, how to be secured, 148, 

365, 366, 432, 433. 
Health, its influence on remem- 
brance, 418, 430. 
Hearing, how aided, 90. 
Hearsay evidence, remarks on, 

216, 226, 227. 
Heat, importance of knowing its 

laws, 360. 
Heat, probable nature of, 362, 444, 

445. 
History, definition and divisions of, 

341-343. 
History, foundations and uses of, 

396," 397, 400. 
History, boundaries of, 397, 39S. 
"■ first merit of, 399. 
" frequent imperfections in, 
399, 400. 
History, two kinds of, 399, 400. 
" study of, 400, 401. 
" traditional, 401,402. 
Homonymous expressions, aber-j 

rancy of, 314. 
Hurry, evils of, 431. 
Hvdric, definition and divisions of, 

334, 335. 
Hvdric, foundations and uses of, 

353. 
Hydrodynamic, definition of, 335. J 

" uses of, 

Hydrology, definition of, 337. 

" sources andusesof,371. 

Hydromechanism,defmitionof,335. 

" uses of, 353. 

Hydrostatic, definition of, 335. 

" uses of, 353. 

Hygiene, definition of, 336. 

" importance of, 366. 
Hypotheses, definition of, 109. 

" uses of, 110-112, 159. 

" why often underval- 

ued, 110. 
Hypotheses, abuse of, 112, 113. 

" modes of testing, 113- 

115. 
Hypotheses, peculiarities of a cer- 
tain class of, 113. 



Hypotheses, phenomenal, 113-1 15. 
" refutation and con- 

firmation of these, 114. 

Hypotheses, preferable, 115, 159. 
" common errors, 115. 

Hypothetical causes, sophism of, 
294. 

Hypothetical proposition, defini- 
tion of, 39. 

Hypothetical truths, nature of, 31. 

I. 

Ideas, definition of, 33. 

" distinctions of, 46, 47. 

' ' trains of, how traceable, 419 

-421. 
Identical proposition, definition of, 

38. 
Identity, personal, remarks on, 93, 

94, 132. 
Idioms, definition of, 195. 

" interpretation of, 204,205. 
Ignorance, evils of, 15-25. 
Ignorant interpretation, paralo- 
gism of, 2S5. 
Illusions, nature of spectral, 72. 
Illusive contradiction, aberrancy 

of, 315. 
Illusive sign, paralogism of, 271- 

273. 
Imaginary absurdity, sophism of, 

304. 
Imaginary apprehension, paralo- 
gism of, 274. 
Imaginary cause, sophism of, 296. 
" effect, sophism of, 297. 
•' quantities, nature of, 

350. 
Imaginary universality, sophism 

of, 292. 
Imagination, nature of, 35, 36. 

" misapplications of, 

| 255, 305. 
Imitations, how distinguished, 131, 

132. 
[Immaterial substances, definition 
| of, 58. 

Immediate cause, definition of, 1 70. 
Immediate knowledge, definition 
| of, 30. 

Immediate testimony, definition of, 
j 226. 
Implications, difficulty regarding, 

207. 208. 



Index. 



457 



Implicit testimony, 226. 

Imponderable substances, defini- 
tion of, 334. 

Imponderable substances, probable 
nature of, 362. 

Impossible quantities, nature of, 
350. 

Impostors, on what chiefly depend- 
ent, 21, 22. 

Inanimate substances, remarks on, 
58, 59. 

Inattention, how the immediate 
source of error, 48, 49, 252, 253. 

Inattention, evils of habitual, 122. 
" causes of, 253, 254. 

Inclusion, principles of, 63-65. 

Incomprehensible connective, soph- 
ism of, 300, 301. 

Incomprehension, paralogism of, 
270,271. 

Inconclusive investigation, soph- 
ism of, 301. 

Indefinite proposition, definition 
of, 39. 

Indefinite terms, aberrancy of, 307, 
308. 

Index, uses of a general, 428, 433. 

Indications (see Signs). 

Indirect discovery, nature of, 154. 
" various observ- 

ations on, 157-162. 

Indirect proof, definition and char- 
acter of, 134, 135. 

Indiscrimination, paralogism of, 
282. 

Individual proposition, definition 
of, 39. 

Indolence, evils of, 125, 126. 

Induction, definition of, 101. 
" requisites to, 101. 
' ' various processes of, 1 1 
-106. 

Induction, on what based, 104, 105. 
" how established, 106, 
107. 

Induction, uses of, 108, 393. 

" advantages of extend- 
ing, 108, 109. 

Induction, aided by classification, 
239. 

Induction, errors regarding, Note 
13, 439, 440. 

Inductive Logic, remarks on, Note 
13,439,440. 



u 



Inertia, remarks on, 83. 
Inferences, definition of, 29, 50, 51. 
' ' requisites to validity of, 

47. 
Inferences, how distinguished, 48. 
" from comprehensions, 

129-134. 
Inferences, from probabilities, 136. 

from testimony, 216. 
Inferring hypotheses, sophism of, 

298, 299. 
Inferring the agreeable, aberrancy 

of, 321. 
Inferring the converse, sophism of, 

288. 
Inferring the probable, sophisms 

of, 298-301. 
Infinitesimal Calculus, remarks on, 

347, Note 22, 442, 443. 
Information, best sources of, 147. 
Inorganical Sciences, definition of, 

334. 
Intellect, definition of, 71 . 
Intentional sense, when to be 

adopted, 203. 
Internal signs, 97. 
Interpretation, nature and use of, 

200. 
Interpretation, objectionable view 

of, Note 16, 441. 
Interpretation, what expressions 

require, 200, 201. 
Interpretation, various rules of, 

201-207. 
Interpretation, frequent sources of 

difficulty, 207, 208. 
Interpretation, use of translations, 

20S. 
Interpretation, influence of preju- 
dices, 208. 
Interpretation, fallacies of, 278- 

280. 
Interrogation, paralogism of, 277. 
Intervals, mnemonic law of, 416. 
Intrinsic probability, remarks on, 

224. 
Intrinsic qualities, 79-85. 
Intuitions, definition and nature 

of, 29, 64. 
Intuitions, knowledge obtained by, 

49. 
Intuitions, admit of no proof, 127, 

128. 
Intuitions, paralogisms of, 266,267. 



458 



Index. 



Intuitions, criterion of, 267. 
Intuitional assumption, paralogism 

of, 266, 267. 
Intuitional rejection, paralogism 

of, 266, 267. 
Invention, nature of, 154. 

" how related to indirect 

discovery, 162. 
Invention, two kinds of, 162. 

" principal fields of, 162, 

163. 
Invention, requisites to success, 

163, 164. 
Invention, various aids in, 164. 
Investigation, dispositions affect- 
ing, 119-121. 
Investigation, habits affecting, 121 

-127. 
Investigation, requisites to success, 

120, 121. 
Investigation, evils of superficial, 

124. (See Proof, Study, and 

Original Investigation.) 
Irrelevant admission, aberrancy of, 

319, 320. 
Irrelevant analogies, aberrancy of, 

308, 309. 
Irrelevant empiricism, aberrancy 

of, 312. 
Irrelevant illustration, aberrancy 

of, 307. 
Irrelevant induction, aberrancy of, 

312. 
Irrelevant modification, aberrancy 

of, 314. 
Irrelevant objection, aberrancy of, 

313. 



Judgements, definition of, 71. 

" other views of, Note 

9, 437, 438. 

Jurisprudence, definition and divis- 
ions of, 338, 339. 

Jurisprudence, nature, founda- 
tions and uses of, 383, 384. 

Jurisprudence, study of, 3S5. 



Knowable, boundaries of the, 30. 
Knowledge, definition of, 30. 

" advantages of, 15-25. 

" requisites in its pur- 
suit, 16, 120, 121,318. 



Knowledge, its limits, 29, 30. 

" its threefold division, 

29. 
Knowledge, how distinguished from 

belief, 30, 265. 
Knowledge, immediate and medi- 
ate, 30, 31. 
Knowledge, necessary, contingent, 

and hypothetical, 31. 
Knowledge, of real beings, on what 

founded, 71. 
Knowledge, mental processes for 

acquiring, 75-85. 
Knowledge, external processes for 

acquiring, 86-93. 
Knowledge, primary modes of re- 
taining and perpetuating, 93-98. 
Knowledge, primary and second- 
ary, 139, 140. 
Knowledge, best sources of, 147. 
" no royal road to, 1-19. 

" test of its amount, 191. 

" table of the means of 

acquiring, 246. 
Knowledge, classification of, 331. 
" scientific, 331-339. 

" mixed, 339, 310. 

" particular, 340, 341. 

" table of, 341-343. 

" of futurity, 405-410. 

" retention of, by simple 
remembrance, 413-425. 
Knowledge, retention of, by exter- 
nal signs, 425-429. 
Knowledge, requisites to a ready 

command of, 429, 430. 
Knowledge, means of acquiring and 

employing these, 431-433. 
Knowledge, table of the means of 

retaining, 434. 
Known, boundaries of the, 30. 



Language, how related to reason- 
ing, 70, 71. 

Language, vernacular, how learn- 
ed, 85. 

Language, importance of under- 
standing, 144, 315. 

Language, origin of, 182, 183. 
" progress of, 1S3-18S. 
" compounding terms, 
whence, 185, 186. 

Language, not of divine origin, 188. 



Index. 



459 



Language, uses of, 189. 
" natural, 189. 
" advantages of speech, 
189, 190. 

Language, three rules of proper ex- 
pression, 190, 191. 

Language, definitions, 192, 193. 
" new terms, when re- 
quired, 193, 194. 

Language, new terms, when to be 
avoided, 194. 

Language, what it represents, 194. 
" imperfections of, 195, 
196. 

Language, abuses of, 196-199. 

" interpretation of, 200- 
208. (See Interpretation.) 

Language, misinterpretation of, 
283-287. 

Language, modes of learning, 385 
-389. (See Philology.) 

Law (see Jurisprudence). 

Laws of habits, 125. 

Laws of health, advantages of at 
tending to, 148, 153. 

Laws of motion, 59, 443. 

" proposed addition 

to, Note 23, 443. 

Laws of nature, how established, 
101-107. 

Laws of nature, superior and sub- 
ordinate, 107. 

Laws of nature, advantages of ex- 
tending, 10S, 109. 

Laws of nature, distinguished from 
empiricisms, 109. 

Laws of nature, what they are 
109, 170. 

Laws of nature, importance of 
knowing, 166, 168, 173, 174 

Laws of nature, not efficient causes, 
295. 

Laws of nature, their uniformity 
and permanence, 407-409. 

Laws of remembrance, 413-425. 

Lectures, characteristics of, 142. 

Letters, origin and spread of, Note 
12, 438, 439. 

Life, criterion of, 364. 

Light, probable nature of, 359, 360. 

Likenesses, different kinds and uses 
of, 97, 98, 426, 438. 

Likenesses, how subservient to re- 
membrance, 93-95, 96-98, 426. 



Lines, mathematical, property of, 

54. 
Liquids, definitions of, 334, 353. 
Literal interpretation, when proper, 

and when not, 201-203. 
Logic, definition of, 13. 

" objectionable definition of, 

Note 1, 435. 
Logic, nature and foundations of, 

13. 
Logic, its proper limits, 14. 

" its objects and uses, 14, 15. 

" study of, 15. 

" remarks on Aristotelian, 

Note 5, 436, 437. 
Logic, error regarding, Note 13, 

439, 440. 
Logic, how distinguished from 

Psychology, 376. 

M. 

Magnetism, definition of, 336. 

" foundations and uses 
of, 361. 

Magnitudes, principles regarding, 
54-58. 

Mannerism, remarks on, 205. 

Manuscripts, means of ascertain- 
ing their origin, 231, 233. 

Manuscripts, tests of their authen- 
ticity, 232, 233. 

Manuscripts, sources of errors in, 
234. 

Manuscripts, means of removing 
sources of errors in, 235-238. 

Many arguments, aberrancy of, 3 1 9. 

Mass, definition of, Note 23, 443. 

Mathematical Geographv, defini- 
tion of, 337. 

Mathematical Geography, founda- 
tions and uses of, 368-370. 

Mathematics, definition and divis- 
ions of, 333, 334, 341. 

Mathematics, peculiarities of, 344- 
346. 

Mathematics, errors regarding,344. 
" uses of, 346, 347. 

" study of, 347-350. 

" effects of exclusive 

study of, 350, 351. 

Matter, definition of, 58. 

" principles regarding, 58-60. 
" its natural tendency, 170, 
179. 



460 



Index. 



Matter, two kinds of, 334. 
Measurement, various modes of, 

87, 89. 
Measures, standard of, 87. 
Mechanic, definition and divisions 

of, 334. 
Mechanic, foundations and uses of, 

352, 353. 
Mechanical properties, definition 

of, 334. 
Mechanical sciences, definition and 

divisions of, 334, 335, 342. 
Mechanical sciences, foundations, 

uses and study of, 352-358. 
Mechanism, definition of, 334. 
Mediate causes, definition of, 170. 
" knowledge, definition of, 

30. 
Mediate knowledge, how establish- 
ed, 34, 93-98, 129. 
Mediate testimony, 226, 227. 
Medical arts, rational bases of, 366, 

367. 
Memory, definition of, 33. 
" uses of, 71, 93, 96. 
" reliability of, 93-95. 
" primary processes of, 93- 

95, 96-98. 
Memory, means of avoiding its 

primary errors, 95, 96. 
Memory, recognition, 95, 96. 
" use of similitudes, 97. 
" safe assumptions regard 

ing, 132. 
Memoiy, sources and safeguards 

of error, 132, 133, 216, 217. 
Memory, how aided by classifica- 
tion, 239, 417. 
Memory, paralogisms of, 274, 275. 

(See Remembrance.) 
Mendacity, paralogisms of, 278- 

280. 
Mental discipline, advantages of, 

23, 24, 374, 375. 
Mental sciences, definition and di- 
visions of, 338, 339, 342, 343. 
Mental sciences, characteristics of, 

374. 
Mental sciences, foundations and 

uses of, 374, 375. 
Mental sciences, study of, 375, 

376. 
Metaphysics, remark on, Note 28 

446. 



Meteorology, definition of, 337. 
" sources and uses of, 

371. 

Method (see System). 

Methodical habits, advantages of, 
122, 123. 

Microscope, uses of, 90, 362, 363. 

Mind, usual tendency of, 265,266. 

Mineralography, definition of, 338. 

Mineralogy, definition and divis- 
ions of, 338. 

Mineralogy, uses and sources of, 
372. 

Miscomprehension, paralogism of, 
269, 270. 

Misconception, paralogism of, 285, 
286. 

Misconstruction,paralogismof,285. 

Misinterpretation, sources of, 207, 
208. 

Misinterpretation, paralogisms of, 
283-287. 

Misinterpreting ambiguities, paral- 
ogism of, 283. 

Misinterpreting technicalities, pa- 
ralogism of, 283. 

Misplacing the accent, paralogism 
of, 284, 285. 

Misrepresentation, paralogisms of, 
278, 279. 

Misrepresenting comprehensions, 
paralogism of, 279. 

Misrepresenting testimony, paral- 
ogism of, 279, 280. 

Mistaking allusions, paralogism of, 
286. 

Mistaking expressions, paralogism 
of, 283. 

Mistaking ideas, paralogism of, 
274, 275. 

Mistaking the chief cause, sophism 
of, 294. 

Mistaking the chief effect, sophism 
of, 294. 

Mistaking the ultimate cause, 
sophism of, 295. 

Mistaking the style, paralogism of, 
284. 

Misunderstanding archaisms, pa- 
ralogism of, 283. 

Mixed knowledge, definition and 
divisions of, 339, 340-343. (See 
Philology, Ethnography, and 
Technology.) 



Index. 



461 



Mnemotecbny, character of, 423. 
Modern opinions, aberrancy of, 

317. 
Momentum, definition of, Note 23, 

443. 
Monuments, mnemonic use of, 425, 

426. 
Moods, remarks on Aristotelian, 

Note 5, 437. 
Moral certainty, nature of, Note 3, 

435. 
Morality, definition of, 338. 

" foundations and import- 
ance of, 3S1, 382. 
Morality, study of, 382, 383. 
Mortifying proofs, sophism of, 303. 
Motion, nature and laws of, 59, 

Note 23, 443. 

N. 

Natural History (see Zoology). 
" Theology, definition of, 
338. 

Natural Theology, foundation and 
importance of, 378, 379. 

Natural Theology, study of, 379. 

Nature, laws of, how established. 
101-107. 

Nature, laws of, superior and sub- 
ordinate, 107. 

Nature, laws of, advantages of ex- 
tending, 108, 109. 

Nature, laws of, distinguishable 
from empiricisms, 109. 

Nature, laws of, importance of 
knowing, 166, 168, 173, 174. 

Nature, laws of, not efficient caus- 
es, 295. 

Nature, hypothesis regarding, Note 
25, 444, 445. 

Nature, uniformity and perma 
nence of, 407-409. 

Necessary implication, definition 
of, 29. 

Necessary qualities, principles re- 
garding, 58-60. 

Necessary truths, nature of, 29, 
31. 

Negative proposition, definition of, 
39. 

Negative quantities, nature of, 
348, 349. 

Nervous system, its influence on 
remembrance, 418. 



New words, remarks on, 193, 194. 

Non-interpretation of signs, paral- 
ogism of, 273, 274. 

Nosology, definition of, 336. 

Notions, definition of, 33. 

Numbers, principles regarding, 54- 
58. 

Numbers, abstract and concrete, 
349. 

O. 

Objection, paralogism of irrele- 
vant, 313. 

Obscure expression, paralogism of, 
277. 

Obscurity, means of avoiding, 191. 
" sources of, 196-198. 

One-sided arguments, sophism of, 
299, 300. 

Ontology, why not a science, Note 
28, 445, 446. 

Opinion, definition of, 49. 

Optic, definition of, 335. 

" foundations and uses of, 
358-360. 

Oral testimony, observations on, 
227, 228. 

Orders, formation of organic, 242, 
243. 

Orders, naming of organic, 243, 
441, 442. 

Ordinary significations of words, 
when to be adopted, and when 
not, 201-203. 

Organic species and genera, prop- 
erties of, 105, 106. 

Organic species and genera, nam- 
ing of, 243, 441, 442. 

Organic specimens, means of pre- 
serving, Note 26, 445. 

Organical sciences, definition of, 
334. 

Organical sciences, divisions of, 
336, 337, 342. 

Organical sciences, characteristics 
and study of, 362, 363. 

Organical sciences, guiding prin- 
ciples in, 363, 364. 

Organisms, classification of, 241- 
244. 

Original investigation, 151-164. 
" " the gener- 

al character of, 151. 

Original investigation, uses of, 1 52. 



462 



Ls T DEX. 



Original investigation, selection of 
subjects, 153. 

Original investigation, prerequi- 
sites to, 153, 15-4. 

Original investigation, methods of, 
154, 155. 

Original investigation, the princi- 
pal rules of, 155. 

Original investigation, direct dis- 
covery, 155, 156. 

Original investigation, indirect dis- 
covery, 156-162. 

Original investigation, invention, 
162-164. 

Overlooking conditions, paralo- 
gism of, 277. 

Overlooking testimony, 282. 

" the alternative, soph- 

ism of, 302. 

Overlooking the idiom, paralogism 
of, 2S4. 



Palaeontology, definition of, 337. 

Paralogisms, definition of, 250. 
" illustration of, 251. 

" of assuming what is 

attempted to be proved, 267- 
269. 

Paralogisms, of comprehension, 
269-271. 

Paralogisms, of signs, 271-274. 

" of memory, 274, 275. 

" of testimony (intrin- 

sic), 275-280. 

Paralogisms, of testimony (extrin- 
sic), 280-282. 

Paralogisms, of misinterpretation, 
2S3-287. 

Paralogisms, table of, 325. 

Particular knowledge, nature of, 
331. 

Particular knowledge, divisions of, 
340, 341, 343. 

(See History, Chronology, and 
Biography.) 

Particular proposition, definition 
of, 39. 

Passions, evil effects of, 119, 422, 
430, 432. 

Passions, distinction, 422, 432. 
" means of moderating, 
432. 

Past, how known, 34, 93-98. 



Pathologv, definition and divisions, 

336, 337. 
Pathology, uses of, 366, 367. 

" two important princi- 
ples, 357. 
Pathology, foundations of, 357. 
Peculiar marks, definition of, 64. 
Perception, definition of, 32. 
Perseverance, advantages of, 125. 
Personal identitv, nature and proof 

of, 93, 94,132. 
Personal observations, advantages 

of, 152. 
Perspicuity,how to be secured, 191. 
Petrology, definition of, 337. 
Phantasm, definition of, 33. 
Philology, definition and divisions 

of, 339, 343. 
Philology, modes of learning a lan- 
guage, 385-389. 
Philology, principles and results of 

comparative, 389, 390. 
Philologv, errors regarding, Note 

30, 446, 447. 
Philology, general, 390, 391. 

" uses of, 391. 
Phonetic writing, nature of, 97. 
" " origin and spread 

of, Note 12, 438, 439. 
Phonetic writing, advantages and 

disadvantages of, 426, 427. 
Phvsical sciences, definition and 

divisions of, 334-338. 
Physical sciences, characteristics 

and study of, 351. 
Physical sciences, uses of, 352. 

" welfare, requisite to, 200. 
Physiology, definition and divisions 

of, 336. 
Physiology, foundations and uses 

of, 365, 366. 
Phytology, definition of, 336. 
Pictures, uses of, 91, 92, 426. 

" disadvantages of, 424, 

425, 426. 
Pneumatic, definition of, 335. 

" foundations and uses 

of, 353, 354. 
Pneumatologv, remark on, Note 

28, -446. 
Point, property of mathematical, 

54. 
Political Economy, remarks on, 

Note 29, 446. 



Index. 



463 



Ponderable matter, definition of, 

334. 
Power, how its nature known, 

Note 7, 437. 
Predicate, definition of, 37. 
Prejudices, evils of, 126, 208. 
' ' rules regarding, 143. 

" influence of, on testi- 
mony, 223, 224. 
Prejudices, influence of, on classi- 
fication, 245. 
Prejudices, nature and general op- 
eration of, 254-256. 
Prejudices, causes of power of,255, 

256, 260. 
Prejudices, several kinds of, 256- 

260. 
Prejudices, combination of, 260. 
" means of guarding 
against, 261,262, 265. 
Premise and inference, mnemonic 

law of, 420. 
Premises, definition of, 50. 

" inaccurate use of, 160. 
Primary premises, definition of, 65 
" " criterions of, 66, 

135-138. 

(See Eeasoning, Evidence, and 
Testimony.) 
Principles of reasoning, 50-65 
" " general prin- 

ciple, 50. 
Principles of reasoning, special 

principles, 52-65. 
Principles of classification, 240- 

242. 
Probability, definition of, 40. 

' ' different kinds of, 40- 

43. 
Probability, general character of, 

43, 44, 223, 224. 
Probability, uses of, 44, 45. 
" resultant, 45. 
' ' how distinguished 

from certainty, 66, 301. 
Probability, reasoning from, 136. 
" circumstantial, 211, 

212. 
Probability, effects of, on testi- 
mony, 222-225. 
Probability, extrinsic and intrinsic, 

223, 224. 
Probability, futile distinctions, 225, 
226. 



Probability, sophisms of, 296-306. 
Probable reasoning, nature of, 136. 
Proof, definition of, 127, 129. 
" what truths require none, 
127-129. 
Proof, twofold division of, 129. 
" what may be admitted as 
proved, 129-134. 
Proof, what propositions require, 

134. 
Proof, two kinds of, 134, 135. 
" general modes of testing, 
134-139. 

(See Deduction, Evidence, and 
Testimony.) 
Properties, extrinsic, 79. 
" intrinsic, 79-85. 
" of organic beings, 105, 
106. 
Properties, essential and non-essen- 
tial, 242. 
Propositions, definition of, 37. 
" parts of, 37, 38. 

a expression of, 38. 

" Aristotelian view of, 

Note 2, 435. 
Propositions, various kinds of, 38, 

39. 
Propositions, ambiguities in, 39. 
" various forms of, 40. 

" combinations of, 40. 

Prototype, definition of, 33. 
Psychology, definition of, 338. 

" boundaries of, 376, 

377. 
Psychology, foundations and im- 
portance of, 377. 
Psychology, study of, 377. 
Pyrrhonism, futility of, Note 14, 
440. 

Q- 

Qualities, extrinsic, 79. 
" intrinsic, 79-85. 

Quantities, principles regarding, 
54-58. 

Quantities, means of accurately 
determining, 86-91. 

Quantities, standards of, 87. 
" negative, 348, 349. 

Quantities, imaginary or impossi- 
ble, 350. 

Quantities, unit of, 87, 346, 355. 
(See Mathematics.) 



464 



Index. 



B. 

Ratiocination, error regarding, 

Note 13, 439, 440. 
Real definitions, nature of, 192. 
Reason, definition of, 33, 49,50. 
Reasoning, definition of, 33,49,50. 
" objectionable views of, 

Notes 4, 5, and 13, 435, 436, 
439, 440. 
Reasoning, general principle of, 50. 
" identity of, in all cases, 

50. 
Reasoning, expression of, 50, 51. 
" special principles of, 

52-65. 
Reasoning, processes of, 65-70. 
" chain of, 65, 66. 

" requisites to validity 

of, 66, 67. 
Reasoning, ultimate foundations 

of, 67, 130. 
Reasoning, modes of testing, 67, 

68, 136-139. 
Reasoning, arguments, 68. 
" combination, 69. 

" why unimpugnable, 70. 

" how related to lan- 

guage, 70, 71. 
Reasoning, aids of, 71. 

" from probabilities, 136. 

" in a circle, paralogism 

of, 268, 269. 
Recognition, nature of, 95, 421. 
Recollection, definition of, 97. 

" operation of, 418, 

419. 
Re-comprehension, mnemonic law 

of, 417. 
Recreation, advantages of, 148. 
Reductio ad absurdum, nature of, 

134, 135. 
Reduction of syllogisms, remark 

on, Note 5, 437. 
Rejecting the disagreeable, aber- 
rancy of, 321, 322. 
Rejecting the improbable, soph- 
isms of, 301-304. 
Rejecting theories, sophism of,302. 
Relations of thoughts, nature and 

general law of, 418. 
Relations of thoughts, two kinds 

of, 419. 
Relations of thoughts, natural, 
419-425. 



Relations of thoughts, remarks on 
artificial, 423. (See Remem- 
brance, and Thoughts.) 
Religion, proper foundation and 

importance of, 378. 
Religious knowledge, only reliable 

sources of, 3S1. 
Remembrance, definition of, 33. 
" nature of, 33. 

" importance of, 34, 

93, 96. 
Remembrance,reliability of, 93-95. 
" recognition, 95, 96. 

" similitudes, 96, 97. 

" primary processes 

of, 93-95, 96-98. 
Remembrance, safe assumptions 

regarding, 132. 
Remembrance, sources and safe- 
guards of error, 132, 133, 216, 
217. 
Remembrance, general laws and 

rules of, 413-419. 
Remembrance, laws of the rela- 
tions of thoughts, 419-425. 
Remembrance, two kinds of, 419. 
" contiguity and suc- 

cession, 419-421. 
Remembrance, resemblance, 421. 
" emotions, 421, 422. 

" contraries, 422, 423. 

" various observa- 

tions on, 423-425. 
Remembrance, external signs, 

425-427. 
Remembrance, writing, 427-429. 
" requisites to readi- 

ness of, 429, 430. 
Remembrance, how these to be se- 
cured, 431-433. 
Repetition, its influence on remem- 
brance, 416. 
Repetition, method of, 87, 88. 
" combination jaf, 89. 

Representations, uses of visible, 

91, 92, 426. 
Representations, uses of tangible, 

92, 93. 

Resemblance, mnemonic law of, 

421. 
Results, how tested, in certain 

cases, 90. 
Retention of knowledge, primary 

processes of, 96-98. 



Index. 



4G5 



Ketention of knowledge, by simple 

remembrance, 413-425. 
Retention of knowledge, relations 

of thoughts, 419-425. 
Retention of knowledge, external 

signs, 425-429. 
Retention of knowledge, writing, 

427-429. 
Revelation, evidences of, 379. 
" importance of, 379. 

" study of, 379-381. 

Reviewing, its importance in study, 

148. 
Reviewing, mnemonic laws, 416, 

417. 
Rhetoric, definition of, 340. 
" uses of, 394, 395. 
Ridicule, its logical character, 

322. 
Rumor, general character of, 226, 

227. 
Rumor, when important, 227. 

S. 
Sages' opinions, aberrancy of, 317, 

318. 
Scepticism, character and origin 

of, 119, 120. 
Scepticism, paralogism, 282. 
Sciences, which dependent on ex- 
perience, 137. 
Sciences, definition of, 331. 
" requisites to, 331, 332. 
" boundaries of, 332, 333 
" three classes of, 333. 
" remarks on some names 
of, Note 19, 442. 
Sciences, table of, 341-343. 

' ' their relations to Art, 392, 
393. 
Sciences, permanence of (see Math- 
ematics, Physical Sciences, and 
Mental Sciences). 
Self-control, advantages of, 126, 

127. 
Self-indulgence, evils of, 126, 127. 
Semeiology, definition of, 336,337. 
Sensations, definition of, 32. 

" proper mode of dealing 

with, 432. 
Senses, credibility of, 71-75. 

" origin of errors attributed 
to, 71, 72, 132. 
Senses, bow to avoid these, 72-75. 
IT 



Senses, subsidiaries of, 86-93. 
Severing probabilities, sophism of, 

302, 303. 
Sight, how aided, 90. 

" cause of its superior power, 

424, 425. 
Signs, definition of, 129. 

" internal and external, 97, 

98, 129. 
Signs, general means of testing, 

135. 
Signs, conclusive, 209. 

" how these ascertainable, 209. 

" probable, 209, 210. 

" value of, how determined, 

210. 
Signs, use of, in aiding testimony, 

222, 223. 
Signs, paralogisms of, 271-274. 

" use of, in aiding remem- 
brance, 425-429. 
Similitudes, definition of, 33. 

" distinctions, 46,47,72, 

73, 96. 
Similitudes, relation of, to remem- 
brance, 97. 
Similitudes, how fading rendered 

precise and vivid, 417. 
Simple proposition, definition of, 

39. 
Singular proposition, 39. 
Sneers, logical character of, 322. 
Sobriety, advantages of, 126, 127, 

418. 
Solid bodies, nature of, 58. 
Solidity, mathematical, 54, 333. 
" resistive, 58. 
" mechanical, 334. 
Solids, properties of mathematical, 

54. 
Sophisms, definition of, 250. 
" illustration of, 251. 
" of confusion, 287-289. 
" of generalization, 289- 

292. 
Sophisms of causation, 292-298. 
" of probability, 298-306. 
" table of, 326. 
Sophistical combination, sophism 

of, 292. 
Sophistical connection, sophism of, 

287, 288. 
Sophistical contraction, sophism 

of, 291. 
o 



466 



Index. 



Sophistical distinction, sophism of, 

304. 
Sophistical exclusion, sophism of, 

291. 
Sophistical explanation, sophism 

of, 295. 
Sophistical extension, sophism of, 

290. 
Sophistical inclusion, sophism of, 

290, 291. 
Sophistical induction, sophism of, 

295. 
Sophistical leap, sophism of, 301. 
" proof, sophism of, 295, 

296. 
Sophistical relation, sophism of, 

296. 
Space, principles regarding, 53, 

54. 
Special interpretation, when to be 

adopted, 202. 
Species, classification of organic, 

241, 242. 
Species, mode of naming, 242, 

Note 17, 441, 442. 
Speech (see Language). 
Specters, nature of, 72. 

" remarkable case, Note 10, 

438. 
Spurious compositions, how distin- 
guished, 230-232. 
Static, definition of, 334. 
Straight line, pi-inciples regarding, 

56-58. 
Study, what acquired by, 139. 

" importance of, 139. 

" general objects of, 139,140. 

" other advantages of, 140. 

" order of, 140. 

" selection of subjects, 140, 

141. 
Study, objects to be considered, 

141. 
Study, extent of, 141. 

" three modes of, 141, 142. 

" of controverted subjects, 

142, 143. 
Study, general rides of, 143-148. 

" prejudices, 143. 

" meaning of terms, 143,144. 

" language, 144. 

" difficulties, 144-146. 

' ' evils of deviations andcram- 

ming, 145. 



Study, advantages of careful and 

thorough, 146. 
Study, testing statements, 146,147. 

" sources of information, 147. 

" simultaneous subjects, 147, 

148. 
Study, recreation, 148. 

" laws of health, 148. 

" final reviewing, 148. 

" selection of books, 148, 149. 

" of books, 150, 151. 

" evil practices of, 150, 151. 

" different from reading, 431, 

432. 
Style, requisites to a good, 190- 

194. 
Subject of a proposition, definition 

of, 37. 
Substances, necessary qualities of, 

58-60. 
Succession, mnemonic law of, 419, 

420. 
Superstition, its origin and remedy, 

22, 23. 
Suppressing truth, paralogism of, 

278, 279. • 
Surfaces, properties of mathemat- 
ical, 54. 
Syllogism, definition of, 50. 

" Aristotelian view of, 

Note 5, 436, 437. 
Syllogism, parts of, 50, 51. 

" various modes of stat- 
ing, 51. 
Syllogism, modes of testing, 66-70. 
" error regarding, Note 

13, 439, 440. 
Symbolic writing, character of, 98. 
Symbols, uses and kinds of, 91-98, 

426. 
Symptomatology, definition of, 336, 

337. 
Synopses, uses of, 264, 417. 
Synthetical Geometry, definition 

of, 334. 
Synthetical Geometry, uses of, 350. 
System, general advantages of, 122, 

123, 430. 
System, mnemonic law of, 417,418. 
" how secured, 127, 431. 



Table of the means of acquiring 
knowledge. 246. 



Index. 



46V 



Table of fallacies, 325-327. 

" of the principal branches of 
knowledge, 341-343. 

Table of the means of retaining 
knowledge, 434. 

Tables, uses of, 428, 429. 

Tangible representations, use of, 
92, 93. 

Technical senses, when to be adopt- 
ed, 202. 

Technology, definition and divis- 
ions of, 339, 340, 343. 
l^See Art.) 

Temperance, advantages of, 126, 
127, 418. 

Terms, uses of general, 36, 190. 
" what these denote, 99. 
" importance of understand- 
ing, 143, 144. 

Terras, understanding of, how to be 
effected, 196, 199, 202. 

Terms, when new requisite, 194. 
" whence these best derived, 
194. 

Terms, when new objectionable, 
194. 

Terms, five classes of, 200, 201 

Testimony, definition of, 129. 

" safe assumptions re- 
garding, 133. 

Testimony, general principle of its 
credibility, 133, 134, 210. 

Testimony, two requisites, 135, 
136. 

Testimony, influence of witness's 
moral character, 210. 

Testimony, importance of, 212, 
213. 

Testimony, criterions of, 213-219 
" general and special, 
213. 

Testimony, concurring testimonies, 
219. 

Testimony, nature of the state 
ments, 219, 220. 

Testimony, discrepancies, 220-222 
" difficulties, how sur- 
mountable, 221, 222. 

Testimony, probable testimony, 222 
-224. 

Testimony, influence of prejudices, 
223, 224. 

Testimony, futile distinctions, 225 
226. 



Testimony, explicit and implicit, 
226. 

Testimony, oral and written, 227, 
228. 

Testimony, effects of lapse of time, 
228, 237. 

Testimony, evidences of author- 
ship, 229-232. 

Testimony, sources of material cor- 
ruptions, 232. 

Testimony, rules regarding these, 
232, 233. 

Testimony, means of ascertaining 
origin of writing, 233. 

Testimony, various readings, 234. 
" rules regarding these, 
235, 236. 

Testimony, authentic and fictitious, 
237. 

Testimony, paralogisms of (intrin- 
sic), 276-280. 

Testimony, paralogisms of (extrin- 
sic), 280-282. 

Theology, definition and divisions 
of, 338. 

Theology, character and founda- 
tions of, 377-379. 

Theology, study of, 379-381. 

Theory, definition of, 114. 

" its relations to Art, 393, 
394. 

Therapeutic, definition of, 337. 
" foundations of, 357. 

Thermotic, definition of, 335. 

" foundations and uses 
of, 360. 

Thinking, six things necessary to, 
36, 37. 

Thinking, source of errors, 37. 

Thoughts, relations of, 419-425. 
" two kinds of, 419. 
" four laws of natural, 
419-423. 

Thoughts, arbitrary relations of, 
423. 

Thoughts, mnemotechny, 423. 

" means of widening the 
range of relations of, 424. 

Time, principles relating to, 53, 54. 

Torture, its effects on testimony, 
218. 

Toxicology, definition of, 336. 

Tradition, remarks on, 401, 402. 

Translations, particular use of, 208. 



468 



Index. 



Truism, eight forms of it, 52, 

53. 
Truisms, definition of, 52. 

" general expression of, 52. 
Truth, general criterion of, 45-48. 
" common error in investiga- 
ting, 119. 
Truth, two extremes, 119, 120. 
" their common origin, 120. 
" proper course, 120. 
" requisites to discovery of, 
120, 121, 261-266. 
Truth, frequent causes of failure, 

120. 
Truth, proper and improper hab- 
its, 121-127. 
Truth, how former to he secured, 

127. 
Truth, necessary, 29, 31, 32. 
" contingent, 31, 32. 
" hypothetical, 31, 32. 
" universal, how known, 52. 
" what requires no proof, 127 
-129. 
Truth, prerequisite to its admis- 
sion, 128. 
Truth, what may be admitted as 

proved, 129-134. 
Truth, what requires formal proof, 

134. 
Types, organic, 242, 243. 

U. 

Ultimate causes, definition of, 170. 
" " what alone are, 

170. 

Ultimate causes, error regarding, 
170. _ 

Unconditional proposition, defini- 
tion of, 39. 

Uniformity of nature, how known, 
101-107. 

Units of measure, 87, 346, 355, 
357. 

Universal belief, aberrancv of, 316, 
317. 

Universal proposition, definition of, 
39. 

Universal truths, only means of 
knowing, 29, 31, 32. 

Universal truths, various expres- 
sions of, 64. 

Usages of language, how learned. 
204. 



Usages of language, how employed 
in interpretation, 203-206. 

Usages of language, which the 
best, and which good, 386, 387. 

Usual significations, when to be 
adopted, 201-203. 



Vagueness of expression, means 

of avoiding, 191-198. 
Vagueness of expression, sources 

of, 196, 197. 
Various readings, sources of, 234. 
" " written and 

printed copies, 234. 
Various readings, rules regarding, 

232, 233, 235, 236. 
Various readings, general charac- 
ter of, 236. 
Varying probability, sophisms of, 

304-306. 
Velocity, principles regarding, 59. 
" actual and virtual, Note 

23, 443. 
Verbal definitions, nature of, 192. 
" " rules regard- 

ing, 192, 193. 
Verbal illusion, aberrancy of, 314, 

315. 
Verification, various methods of, 

90. 
Vernacidar language, how first 

learned, 85. 
Vicious circle, paralogism of, 268, 

269. 
Visible representations, uses of, 91, 

92, 426. 
Volition, definition of, 62. 

" principles regarding, 62, 

63. 
Volition, error regarding, Note 1 1 , 

438. 
Volition, changes caused by, 75-79. 

W. 

Weights, standard of, S7. 

Wisdom, requisites to, 16, 17. 

Witnesses (see Testimony). 

Words (see Expressions, Lan- 
guage, and Terms). 

Writing, origin and spread of, Note 
12, 438, 439. 

Writing, uses of, 141, 142, 148, 
22S, 426, 427. 



Index. 



469 



Writing, retention of knowledge 
by, 427-429. 

Writing, common error regarding, 
433. 

Writing, means of rendering avail- 
able, 433. 

Written testimony, remarks on, 
227-237. (See Testimony.) 



Wrong expression, paralogism of, 
277, 278. 



Zoology, definition and divisions 

of, 336. 
Zoology, foundations and uses of, 

364, 365. 



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